passenger revenues fare revenues . tickets sold are initially deferred within air traffic liability on the company 's balance sheet . passenger fare revenues are recognized at time of departure when transportation is provided . all tickets sold by the company are nonrefundable . an unused ticket expires at the date of scheduled travel and is recognized as revenue at the date of scheduled travel . passenger revenues reported prior to the adoption of asu 2014-09 are now reported as fare revenues within passenger revenues in the company 's disaggregated revenue table within “ notes to the financial statements— 4 , revenue disaggregation . `` non-fare revenues . our most significant non-fare revenues include revenues generated from air travel-related services paid for baggage , passenger usage fees , advance seat selection , itinerary changes , and loyalty programs . the adoption of asu 39 2014-09 impacted the classification of these ancillary items since they are deemed part of the single performance obligation of providing passenger transportation . these ancillary items are now recognized in non-fare revenues within passenger revenues in the company 's disaggregated revenue table within “ notes to the financial statements— 4 , revenue disaggregation . `` passenger non-fare revenues are recognized at time of departure when transportation is provided . passenger revenues are recognized once the related flight departs . accordingly , the value of tickets and non-fare revenues sold in advance of travel is included under our current liabilities as “ air traffic liability , ” or atl , until the related air travel is provided . revenue generated from the free spirit credit card affinity program are recognized in accordance with the criteria as set forth in accounting standards update asu 2014-09. please see “ —critical accounting policies and estimates—frequent flyer program . ” other revenues other revenues primarily consist of the marketing component of the sale of frequent flyer miles to our credit card partner and commissions revenue from the sale of various items such as hotels and rental cars . substantially all of our revenues are denominated in u.s. dollars . we recognize revenues net of certain taxes and airport passenger fees , which are collected by us on behalf of airports and governmental agencies and remitted to the applicable governmental entity or airport on a periodic basis . these taxes and fees include u.s. federal transportation taxes , federal security charges , airport passenger facility charges and foreign arrival and departure taxes . these items are collected from customers at the time they purchase their tickets , but are not included in our revenues . upon collection from the customer , we record a liability within other current liabilities on our balance sheets and relieve the liability when payments are remitted to the applicable governmental agency or airport . operating expenses our operating expenses consist of the following line items . aircraft fuel . aircraft fuel expense includes the cost of jet fuel , related federal taxes , fueling into-plane fees and transportation fees . it also includes realized and unrealized gains and losses arising from activity on our fuel derivatives , if any . our fuel derivatives , if any , generally consist of united states gulf coast jet fuel swaps ( `` jet fuel swaps `` ) and united states gulf coast jet fuel options ( `` jet fuel options `` ) . salaries , wages and benefits . salaries , wages and benefits expense includes the salaries , hourly wages , bonuses and equity compensation paid to employees for their services , as well as the related expenses associated with employee benefit plans and employer payroll taxes . landing fees and other rents . landing fees and other rents include both fixed and variable facilities expenses , such as the fees charged by airports for the use or lease of airport facilities , overfly fees paid to other countries and the monthly rent paid for our headquarters facility . aircraft rent . aircraft rent expense consists of all minimum lease payments under the terms of our aircraft and spare engine lease agreements recognized on a straight-line basis . aircraft rent expense also includes supplemental rent . supplemental rent is made up of maintenance reserves paid to aircraft lessors in advance of the performance of major maintenance activities that are not probable of being reimbursed and probable and estimable return condition obligations . aircraft rent expense is net of the amortization of gains and losses on sale leaseback transactions on our flight equipment . as of december 31 , 2018 , 46 of our 128 aircraft and 12 of our 20 spare engines are financed under operating leases . depreciation and amortization . depreciation and amortization expense includes the depreciation of fixed assets we own and leasehold improvements . it also includes the amortization of capitalized software costs and heavy maintenance . under the deferral method , the cost of our heavy maintenance is capitalized and amortized on a straight-line or usage basis until the earlier of the next estimated heavy maintenance event or the remaining lease term . distribution . distribution expense includes all of our direct costs , including the cost of web support , our third-party call center , travel agent commissions and related gds fees and credit card transaction fees , associated with the sale of our tickets and other products and services . maintenance , materials and repairs . maintenance , materials and repairs expense includes parts , materials , repairs and fees for repairs performed by third-party vendors and in-house mechanics required to maintain our fleet . it excludes direct labor 40 cost related to our own mechanics , which is included under salaries , wages and benefits . it also excludes the amortization of heavy maintenance expenses , which we defer under the deferral method of accounting and amortize as a component of depreciation and amortization expense . special charges . story_separator_special_tag please see “ —critical accounting policies and estimates—aircraft maintenance , materials , repair costs and related heavy maintenance amortization ” and “ —maintenance reserves . ” critical accounting policies and estimates the following discussion and analysis of our financial condition and results of operations is based on our financial statements , which have been prepared in accordance with accounting principles generally accepted in the united states . the preparation of these financial statements requires us to make estimates and judgments that affect the reported amount of assets and liabilities , revenues and expenses and related disclosure of contingent assets and liabilities at the date of our financial statements . for a detailed discussion of our significant accounting policies , refer to “ notes to financial statements—1 . summary of significant accounting policies . ” critical accounting policies are defined as those policies that reflect significant judgments or estimates about matters both inherently uncertain and material to our financial condition or results of operations . revenue recognition . revenues from tickets sold are initially deferred as atl . passenger revenues are recognized when transportation is provided . an unused non-refundable ticket expires at the date of scheduled travel and is recognized as revenue for the expired ticket value at the date of scheduled travel . as of december 31 , 2018 and 2017 , we had air traffic liability ( `` atl `` ) balances of $ 292.0 million and $ 263.7 million , respectively . as of december 31 , 2018 , all of the atl balance as of december 31 , 2017 has been recognized . customers may elect to change or cancel their itinerary prior to the date of departure . for changes , a service charge is recognized at time of departure of newly scheduled travel and is deducted from the face value of the original purchase price of the ticket , and the original ticket becomes invalid . for cancellations , a service charge is assessed and the amount remaining after deducting the service charge is called a credit shell which generally expires 60 days from the date the credit shell is created and can be used towards the purchase of a new ticket and the company 's other service offerings . both the service charge and credit shell amounts are recorded as deferred revenue and amounts expected to expire unused are estimated based on historical experience . estimating the amount of credits that will go unused involves some level of subjectivity and judgment . however , given the relatively short period of time to expiration , this does not have a significant impact on the company 's financial statements . frequent flyer program . our frequent flyer program generates customer loyalty by rewarding customers with mileage credits to travel on spirit . when traveling , customers earn redeemable mileage credits for each mile flown on spirit . customers can also earn mileage credits through participating companies such as the co-branded spirit credit card . mileage credits are redeemable by customers in future periods for air travel on spirit . to reflect the mileage credits earned , the program includes two types of transactions that are considered revenue arrangements with multiple performance obligations : ( 1 ) mileage credits earned with travel and ( 2 ) mileage credits sold to co-branded credit card partner . the adoption of asu 2014-09 eliminated the incremental cost method for frequent flyer program accounting , which required us to re-value and record a liability associated with customer flight miles earned with travel as part of our frequent flyer program with a relative fair value . upon adoption of asu 2014-09 on january 1 , 2018 , we recorded an increase to our air traffic liability of $ 12.4 million . passenger ticket sales earning mileage credits . passenger ticket sales earning mileage credits provide customers with ( 1 ) mileage credits earned and ( 2 ) air transportation . we value each performance obligation on a standalone basis . to value the mileage credits earned , we consider the quantitative value a passenger receives by redeeming miles for a ticket rather than paying cash , which is referred to as equivalent ticket value ( `` etv `` ) . we defer revenue for the mileage credits when earned and recognize loyalty travel awards in passenger revenue as the miles are redeemed and services are provided . we record the air transportation portion of the passenger ticket sales in air traffic 44 liability and recognize passenger revenue when transportation is provided or if the ticket goes unused , at the date of scheduled travel . sale of mileage credits . customers may earn mileage credits based on their spending with our co-branded credit card company with which we have an agreement to sell mileage credits . the contract to sell mileage credits under this agreement has multiple performance obligations . during the year ended december 31 , 2018 and 2017 , total cash sales from this agreement were $ 39.2 million and $ 49.5 million , respectively , which are allocated to travel and other performance obligations . our co-brand credit card agreement provides for joint marketing where cardholders earn mileage credits for making purchases using co-branded cards . during 2015 , we extended its agreement with the administrator of the free spirit affinity credit card program to extend through 2022. we account for this agreement consistently with the accounting method that allocates the consideration received to the individual products and services delivered . the value is allocated based on the relative selling prices of those products and services , which generally consists of ( i ) travel miles to be awarded , ( ii ) licensing of brand and access to member lists and ( iii ) advertising and marketing efforts . we determined the best estimate of the selling prices by considering discounted cash flow analysis using multiple inputs and assumptions , including : ( 1 ) the expected

net cash provided by financing activities . during 2018 , financing activities provided $ 481.1 million . we received $ 832.1 million in connection with the 2015-1c and 2017-1c eetcs and the debt financing of 14 aircraft delivered during 2018 . in addition , we paid $ 137.3 million in debt principal payment obligations and $ 205.7 million in capital lease obligations . the payments on capital lease obligations are primarily related to an aircraft purchase agreement for the purchase of 14 a319 aircraft which we previously operated under operating leases . for additional information , refer to `` notes to financial statements - 5. special charges . '' during 2017 , financing activities provided $ 466.7 million . we received $ 629.7 million in connection with the debt financing of 17 aircraft delivered during 2017. we spent $ 46.6 million to repurchase common stock primarily under our stock repurchase authorization , which became effective in october 2017 , and we paid $ 102.3 million in debt principal payment obligations related to the financing of our aircraft . during 2016 , financing activities provided $ 249.9 million . we received $ 417.3 million in connection with the debt financing of 11 aircraft delivered during 2016. we spent $ 102.5 million to repurchase common stock primarily under our stock repurchase authorization , which became effective in october 2015 , and we paid $ 64.4 million in debt principal payment obligations related to the financing of our aircraft . commitments and contractual obligations we have contractual obligations and commitments primarily with regard to future purchases of aircraft and engines , payment of debt , and lease arrangements . the following table discloses aggregate information about our contractual obligations as of december 31 , 2018 and the periods in which payments are due ( in millions ) : replace_table_token_21_th 58 ( 1 ) includes principal only associated with senior and junior term loans , fixed-rate loans , class a , class b , and class c series 2015-1 eetcs , class aa , class a , class b , and class c series 2017-1 eetcs , and our revolving credit facility .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```net cash provided by financing activities . during 2018 , financing activities provided $ 481.1 million . we received $ 832.1 million in connection with the 2015-1c and 2017-1c eetcs and the debt financing of 14 aircraft delivered during 2018 . in addition , we paid $ 137.3 million in debt principal payment obligations and $ 205.7 million in capital lease obligations . the payments on capital lease obligations are primarily related to an aircraft purchase agreement for the purchase of 14 a319 aircraft which we previously operated under operating leases . for additional information , refer to `` notes to financial statements - 5. special charges . '' during 2017 , financing activities provided $ 466.7 million . we received $ 629.7 million in connection with the debt financing of 17 aircraft delivered during 2017. we spent $ 46.6 million to repurchase common stock primarily under our stock repurchase authorization , which became effective in october 2017 , and we paid $ 102.3 million in debt principal payment obligations related to the financing of our aircraft . during 2016 , financing activities provided $ 249.9 million . we received $ 417.3 million in connection with the debt financing of 11 aircraft delivered during 2016. we spent $ 102.5 million to repurchase common stock primarily under our stock repurchase authorization , which became effective in october 2015 , and we paid $ 64.4 million in debt principal payment obligations related to the financing of our aircraft . commitments and contractual obligations we have contractual obligations and commitments primarily with regard to future purchases of aircraft and engines , payment of debt , and lease arrangements . the following table discloses aggregate information about our contractual obligations as of december 31 , 2018 and the periods in which payments are due ( in millions ) : replace_table_token_21_th 58 ( 1 ) includes principal only associated with senior and junior term loans , fixed-rate loans , class a , class b , and class c series 2015-1 eetcs , class aa , class a , class b , and class c series 2017-1 eetcs , and our revolving credit facility .
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 Suspicious Activity Report : passenger revenues fare revenues . tickets sold are initially deferred within air traffic liability on the company 's balance sheet . passenger fare revenues are recognized at time of departure when transportation is provided . all tickets sold by the company are nonrefundable . an unused ticket expires at the date of scheduled travel and is recognized as revenue at the date of scheduled travel . passenger revenues reported prior to the adoption of asu 2014-09 are now reported as fare revenues within passenger revenues in the company 's disaggregated revenue table within “ notes to the financial statements— 4 , revenue disaggregation . `` non-fare revenues . our most significant non-fare revenues include revenues generated from air travel-related services paid for baggage , passenger usage fees , advance seat selection , itinerary changes , and loyalty programs . the adoption of asu 39 2014-09 impacted the classification of these ancillary items since they are deemed part of the single performance obligation of providing passenger transportation . these ancillary items are now recognized in non-fare revenues within passenger revenues in the company 's disaggregated revenue table within “ notes to the financial statements— 4 , revenue disaggregation . `` passenger non-fare revenues are recognized at time of departure when transportation is provided . passenger revenues are recognized once the related flight departs . accordingly , the value of tickets and non-fare revenues sold in advance of travel is included under our current liabilities as “ air traffic liability , ” or atl , until the related air travel is provided . revenue generated from the free spirit credit card affinity program are recognized in accordance with the criteria as set forth in accounting standards update asu 2014-09. please see “ —critical accounting policies and estimates—frequent flyer program . ” other revenues other revenues primarily consist of the marketing component of the sale of frequent flyer miles to our credit card partner and commissions revenue from the sale of various items such as hotels and rental cars . substantially all of our revenues are denominated in u.s. dollars . we recognize revenues net of certain taxes and airport passenger fees , which are collected by us on behalf of airports and governmental agencies and remitted to the applicable governmental entity or airport on a periodic basis . these taxes and fees include u.s. federal transportation taxes , federal security charges , airport passenger facility charges and foreign arrival and departure taxes . these items are collected from customers at the time they purchase their tickets , but are not included in our revenues . upon collection from the customer , we record a liability within other current liabilities on our balance sheets and relieve the liability when payments are remitted to the applicable governmental agency or airport . operating expenses our operating expenses consist of the following line items . aircraft fuel . aircraft fuel expense includes the cost of jet fuel , related federal taxes , fueling into-plane fees and transportation fees . it also includes realized and unrealized gains and losses arising from activity on our fuel derivatives , if any . our fuel derivatives , if any , generally consist of united states gulf coast jet fuel swaps ( `` jet fuel swaps `` ) and united states gulf coast jet fuel options ( `` jet fuel options `` ) . salaries , wages and benefits . salaries , wages and benefits expense includes the salaries , hourly wages , bonuses and equity compensation paid to employees for their services , as well as the related expenses associated with employee benefit plans and employer payroll taxes . landing fees and other rents . landing fees and other rents include both fixed and variable facilities expenses , such as the fees charged by airports for the use or lease of airport facilities , overfly fees paid to other countries and the monthly rent paid for our headquarters facility . aircraft rent . aircraft rent expense consists of all minimum lease payments under the terms of our aircraft and spare engine lease agreements recognized on a straight-line basis . aircraft rent expense also includes supplemental rent . supplemental rent is made up of maintenance reserves paid to aircraft lessors in advance of the performance of major maintenance activities that are not probable of being reimbursed and probable and estimable return condition obligations . aircraft rent expense is net of the amortization of gains and losses on sale leaseback transactions on our flight equipment . as of december 31 , 2018 , 46 of our 128 aircraft and 12 of our 20 spare engines are financed under operating leases . depreciation and amortization . depreciation and amortization expense includes the depreciation of fixed assets we own and leasehold improvements . it also includes the amortization of capitalized software costs and heavy maintenance . under the deferral method , the cost of our heavy maintenance is capitalized and amortized on a straight-line or usage basis until the earlier of the next estimated heavy maintenance event or the remaining lease term . distribution . distribution expense includes all of our direct costs , including the cost of web support , our third-party call center , travel agent commissions and related gds fees and credit card transaction fees , associated with the sale of our tickets and other products and services . maintenance , materials and repairs . maintenance , materials and repairs expense includes parts , materials , repairs and fees for repairs performed by third-party vendors and in-house mechanics required to maintain our fleet . it excludes direct labor 40 cost related to our own mechanics , which is included under salaries , wages and benefits . it also excludes the amortization of heavy maintenance expenses , which we defer under the deferral method of accounting and amortize as a component of depreciation and amortization expense . special charges . story_separator_special_tag please see “ —critical accounting policies and estimates—aircraft maintenance , materials , repair costs and related heavy maintenance amortization ” and “ —maintenance reserves . ” critical accounting policies and estimates the following discussion and analysis of our financial condition and results of operations is based on our financial statements , which have been prepared in accordance with accounting principles generally accepted in the united states . the preparation of these financial statements requires us to make estimates and judgments that affect the reported amount of assets and liabilities , revenues and expenses and related disclosure of contingent assets and liabilities at the date of our financial statements . for a detailed discussion of our significant accounting policies , refer to “ notes to financial statements—1 . summary of significant accounting policies . ” critical accounting policies are defined as those policies that reflect significant judgments or estimates about matters both inherently uncertain and material to our financial condition or results of operations . revenue recognition . revenues from tickets sold are initially deferred as atl . passenger revenues are recognized when transportation is provided . an unused non-refundable ticket expires at the date of scheduled travel and is recognized as revenue for the expired ticket value at the date of scheduled travel . as of december 31 , 2018 and 2017 , we had air traffic liability ( `` atl `` ) balances of $ 292.0 million and $ 263.7 million , respectively . as of december 31 , 2018 , all of the atl balance as of december 31 , 2017 has been recognized . customers may elect to change or cancel their itinerary prior to the date of departure . for changes , a service charge is recognized at time of departure of newly scheduled travel and is deducted from the face value of the original purchase price of the ticket , and the original ticket becomes invalid . for cancellations , a service charge is assessed and the amount remaining after deducting the service charge is called a credit shell which generally expires 60 days from the date the credit shell is created and can be used towards the purchase of a new ticket and the company 's other service offerings . both the service charge and credit shell amounts are recorded as deferred revenue and amounts expected to expire unused are estimated based on historical experience . estimating the amount of credits that will go unused involves some level of subjectivity and judgment . however , given the relatively short period of time to expiration , this does not have a significant impact on the company 's financial statements . frequent flyer program . our frequent flyer program generates customer loyalty by rewarding customers with mileage credits to travel on spirit . when traveling , customers earn redeemable mileage credits for each mile flown on spirit . customers can also earn mileage credits through participating companies such as the co-branded spirit credit card . mileage credits are redeemable by customers in future periods for air travel on spirit . to reflect the mileage credits earned , the program includes two types of transactions that are considered revenue arrangements with multiple performance obligations : ( 1 ) mileage credits earned with travel and ( 2 ) mileage credits sold to co-branded credit card partner . the adoption of asu 2014-09 eliminated the incremental cost method for frequent flyer program accounting , which required us to re-value and record a liability associated with customer flight miles earned with travel as part of our frequent flyer program with a relative fair value . upon adoption of asu 2014-09 on january 1 , 2018 , we recorded an increase to our air traffic liability of $ 12.4 million . passenger ticket sales earning mileage credits . passenger ticket sales earning mileage credits provide customers with ( 1 ) mileage credits earned and ( 2 ) air transportation . we value each performance obligation on a standalone basis . to value the mileage credits earned , we consider the quantitative value a passenger receives by redeeming miles for a ticket rather than paying cash , which is referred to as equivalent ticket value ( `` etv `` ) . we defer revenue for the mileage credits when earned and recognize loyalty travel awards in passenger revenue as the miles are redeemed and services are provided . we record the air transportation portion of the passenger ticket sales in air traffic 44 liability and recognize passenger revenue when transportation is provided or if the ticket goes unused , at the date of scheduled travel . sale of mileage credits . customers may earn mileage credits based on their spending with our co-branded credit card company with which we have an agreement to sell mileage credits . the contract to sell mileage credits under this agreement has multiple performance obligations . during the year ended december 31 , 2018 and 2017 , total cash sales from this agreement were $ 39.2 million and $ 49.5 million , respectively , which are allocated to travel and other performance obligations . our co-brand credit card agreement provides for joint marketing where cardholders earn mileage credits for making purchases using co-branded cards . during 2015 , we extended its agreement with the administrator of the free spirit affinity credit card program to extend through 2022. we account for this agreement consistently with the accounting method that allocates the consideration received to the individual products and services delivered . the value is allocated based on the relative selling prices of those products and services , which generally consists of ( i ) travel miles to be awarded , ( ii ) licensing of brand and access to member lists and ( iii ) advertising and marketing efforts . we determined the best estimate of the selling prices by considering discounted cash flow analysis using multiple inputs and assumptions , including : ( 1 ) the expected

