2017 passenger revenue passenger revenue was $ 2.60 billion and $ 2.49 billion for the years ended december 31 , 2018 and 2017 , respectively . details of these changes are described in the table below : replace_table_token_6_th domestic revenue increased by $ 58.9 million driven by a 2.7 % increase in passengers flown on our domestic routes , partially offset by a 1.2 % decline in average fares . unit revenue declines primarily resulted from capacity growth in the region , specifically between hawai ' i and north america , combined with a reduction in travel attributed to weather-related events impacting the state of hawai ' i . international revenue increased by $ 57.0 million for the year ended december 31 , 2018 as compared to the prior year period driven by a combination of increased passenger counts and average fares , which outpaced capacity growth . in 2017 , we completed the upgrade of our first class cabin and extra comfort seating products on our a330 aircraft , which are driving improvements in profitability and unit revenue growth . during the year we expanded our operations and now have direct routes between maui , hawai ' i and portland , oregon ( january 2018 ) , kona , hawai ' i and los angeles , california ( march 2018 ) , lihue , hawai ' i and los angeles , california ( may 2018 ) , honolulu , hawai ' i and long beach , california ( may 2018 ) , maui , hawai ' i and san diego , california ( june 2018 ) , and lihue , hawai ' i and oakland , california ( july 2018 - expansion to daily service ) . in october 2018 , we suspended our thrice-weekly nonstop service between honolulu , hawai ' i and beijing , china . in september 2018 , we announced our new direct route between honolulu , hawai ' i and boston , massachusetts , which will commence in april 2019. during the first quarter of 2019 , we will have retired our last boeing 767-300 aircraft , completing the transition to our a321 aircraft , allowing for optimization of our products and better capacity management . other operating revenue other operating revenue increased by $ 46.3 million , or 24.6 % , in 2018 , as compared to 2017 , primarily due to an increase in loyalty program revenue of $ 31.8 million related to brand usage associated with our co-brand credit card partnership with barclays , which was amended in the first quarter of 2018. refer to note 1 in the consolidated financial statements for additional information . cargo revenue was up $ 9.0 million as a result of increased freight volumes and the introduction of our inter-island cargo freighter operation in the fourth quarter of 2018. operating expenses during the year ended december 31 , 2018 , total operating expense increased $ 311.9 million or 14.1 % to $ 2.5 billion as compared to the same period in 2017. the largest components of our operating expenses are wages and benefits provided to our 27 employees and aircraft fuel ( including taxes and delivery ) . increases ( decreases ) in operating expenses are detailed below . replace_table_token_7_th aircraft fuel the price and availability of aircraft fuel is volatile due to global economic and geopolitical factors that we can neither control nor accurately predict . the increases in aircraft fuel expense are illustrated in the following table : replace_table_token_8_th the increase in fuel expense from 2017 to 2018 is due to an increase in average fuel price per gallon and increased fuel consumption driven by capacity growth . we believe economic fuel expense is the best measure of the effect of fuel prices on our business as it most closely approximates the net cash outflow associated with the purchase of fuel for our operations and is consistent with how management manages our business and assesses our operating performance . we define economic fuel expense as gaap fuel expense plus ( gains ) /losses realized through actual cash ( receipts ) /payments received from or paid to hedge counterparties for fuel hedge derivative contracts settled in the period inclusive of costs related to hedging premiums . economic fuel expense is calculated as follows : replace_table_token_9_th 28 see item 7a , quantitative and qualitative disclosures about market risk , for additional discussion of our jet fuel costs and related derivative program . wages and benefits wages and benefits expense increased by $ 51.7 million , or 8.2 % , in 2018 , as compared to 2017 , primarily driven by increased overall headcount ( up 8.8 % in 2018 ) . the higher wages and benefits expenses also reflected an increase in cost incurred for training to prepare for the induction of our a321neo fleet which entered service during 2018. maintenance materials and repairs maintenance materials and repairs increased $ 20.2 million , or 9.2 % , in 2018 , as compared to 2017. on a per asm basis , maintenance , materials , and repairs expense increased 2.9 % as compared to the prior year , primarily due to an increase in the number of airframe and engine maintenance events , higher cost of materials for aging aircraft , and an increase in rates on our power by hour contract . aircraft and passenger servicing aircraft and passenger servicing expenses increased $ 12.9 million , or 8.9 % , in 2018 , as compared to 2017 , resulting from higher food and beverage expenses attributed to increased passenger counts ( up 2.9 % in 2018 ) and an increase in ground handling services reflective of increased operations in domestic and international markets . story_separator_special_tag loss ( gain ) on sale of aircraft is the result of adjustments to the final purchase price for three of our boeing 767-300 aircraft included in a forward sale agreement we entered into in january 2018 and described below . during the twelve months ended december 31 , 2018 , we recorded a loss of $ 0.3 million . 2016 special items an impairment analysis and ultimate charge was triggered by the decision in the fourth quarter of 2016 to exit our boeing 767-300 fleet in 2018. we estimated the fair value of the owned boeing 767-300 fleet assets using third party pricing information and quotes from potential buyers , which resulted in a $ 49.4 million impairment charge . in 2016 , we accrued $ 34.0 million associated with the tentative agreement with alpa related to past service ( prior to january 1 , 2017 ) and also elected to pay a $ 4.8 million profit sharing bonus payment to other labor groups related to prior period service . in connection with the decision to exit the boeing 767-300 fleet , we negotiated a termination of our boeing 767-300 maintenance agreement and recorded a $ 21.0 million charge related to the amount paid to terminate the contract . 2017 special items in august 2017 , we terminated the hawaiian airlines , inc. salaried & iam merged pension plan ( the merged plan ) and settled a portion of our pilots ' other post-retirement medical plan liability . in connection with the reduction of these liabilities we recorded one-time other nonoperating special charges of $ 35.2 million related to the merged plan termination and $ 10.4 million related to the other post-retirement ( opeb ) medical plan partial settlement . in april 2017 , we executed a sale leaseback transaction with an independent third party for three boeing 767-300 aircraft . the lease terms for the three aircraft commenced in april 2017 and end between november 2018 and january 2019. during the twelve months ended december 31 , 2017 , we recorded a loss on sale of aircraft of $ 4.8 million . in february 2017 , we reached a tentative agreement with alpa , covering our pilots . in march 2017 , we received notice from alpa that the agreement was ratified by alpa 's members . the agreement became effective april 1 , 2017 and has a term of 63 months . the agreement includes , among other various benefits , a pay adjustment and ratification bonus computed based on previous service . during the twelve months ended december 31 , 2017 , we expensed $ 18.7 million primarily related to a one-time payment to reduce our future 401k employer contribution for certain pilot groups , which is not recoverable once paid . 2018 contract terminations expense during the twelve months ended december 31 , 2018 , we terminated two contracts which incurred a total of $ 35.3 million in contract terminations expense . the transactions are described below : ◦ in february 2018 , we exercised our right to terminate our aircraft purchase agreement with airbus for six airbus a330-800neo aircraft and the purchase rights for an additional six airbus a330-800neo aircraft . to terminate the purchase agreement , we were obligated to repay airbus for concessions received relating to a prior firm order , training credits , as well as forfeit the pre-delivery progress payments made towards the flight equipment . we recorded a contract terminations expense to reflect the termination penalty in our consolidated statements of operations . 36 ◦ in january 2018 , we entered into a transaction with our lessor to early terminate and purchase three boeing 767-300 aircraft leases and concurrently entered into a forward sale agreement for the same three boeing 767-300 aircraft , including two pratt & whitney 4060 engines for each aircraft . these aircraft were previously accounted for as operating leases . in order to exit the lease and purchase the aircraft , we agreed to pay a total of $ 67.1 million ( net of all deposits ) of which a portion was expensed immediately and recognized as a contract termination fee . the expensed amount represents the total purchase price amount over fair value of the aircraft purchased as of the date of the transaction . we believe that excluding such special items helps investors analyze our operational performance and compare our results to other airlines in the periods presented below . replace_table_token_17_th operating costs per available seat mile ( casm ) we have separately listed in the table below our fuel costs per asm and non-gaap unit costs , excluding fuel and special items . these amounts are included in casm , but for internal purposes we consistently use cost metrics that exclude fuel and special items ( if applicable ) to measure and monitor its costs . 37 casm and casm , excluding fuel , loss on sale of aircraft , contract terminations expense , and special items , are summarized in the table below : replace_table_token_18_th critical accounting policies and estimates the discussion and analysis of our financial condition and results of operations are based upon financial statements that have been prepared in accordance with u.s. generally accepted accounting principles . the preparation of these financial statements requires management to make estimates and judgments that affect the reported amount of assets and liabilities , revenue and expenses , and related disclosure of contingent assets and liabilities as of the date of the financial statements . actual results could differ from those estimates . critical accounting policies and estimates are defined as those accounting policies and accounting estimates that are reflective of significant judgments and uncertainties , and that potentially result in materially different results under different assumptions and conditions . our most critical accounting policies and estimates are described below . see the summary of significant accounting policies included in note 1 to the consolidated financial statements for additional discussion of the

liquidity and capital resources our primary sources of liquidity are : 32 our existing cash and cash equivalents and short-term investments of $ 500.8 million , and our expected cash from operations ; our 21 unencumbered aircraft in our aircraft fleet as of december 31 , 2018 , that could be financed , if necessary ; and our $ 235.0 million revolving credit facility with no outstanding borrowing . information about this facility can be found in note 8 to the consolidated financial statements . at december 31 , 2018 , we had $ 709.8 million of debt and capital lease obligations , including $ 101.1 million classified as a current liability in the consolidated balance sheets . as of december 31 , 2018 , our current liabilities exceeded our current assets by approximately $ 301.0 million . however , approximately $ 603.7 million of our current liabilities are related to our advanced ticket sales and frequent flyer deferred revenue , both of which largely represent revenue to be recognized for travel within the next 12 months and not actual cash outlays . the deficit in working capital does not have an adverse impact to our cash flows , liquidity , or operations . cash flows net cash provided by operating activities was $ 508.5 million , $ 331.1 million , and $ 437.0 million in 2018 , 2017 , and 2016 , respectively . operating cash flows are primarily derived from providing air transportation to customers . the vast majority of tickets are purchased in advance of when travel is provided , and in some cases , several months before the anticipated travel date . operating cash outflows are related to the recurring expenses of the airline operations . the operating cash flows for 2018 , 2017 , and 2016 were impacted primarily by our results of operations , adjusted for non-cash items as well as changes in the air traffic liability , accounts receivables and other asset and liabilities , net .


 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.
     ```liquidity and capital resources our primary sources of liquidity are : 32 our existing cash and cash equivalents and short-term investments of $ 500.8 million , and our expected cash from operations ; our 21 unencumbered aircraft in our aircraft fleet as of december 31 , 2018 , that could be financed , if necessary ; and our $ 235.0 million revolving credit facility with no outstanding borrowing . information about this facility can be found in note 8 to the consolidated financial statements . at december 31 , 2018 , we had $ 709.8 million of debt and capital lease obligations , including $ 101.1 million classified as a current liability in the consolidated balance sheets . as of december 31 , 2018 , our current liabilities exceeded our current assets by approximately $ 301.0 million . however , approximately $ 603.7 million of our current liabilities are related to our advanced ticket sales and frequent flyer deferred revenue , both of which largely represent revenue to be recognized for travel within the next 12 months and not actual cash outlays . the deficit in working capital does not have an adverse impact to our cash flows , liquidity , or operations . cash flows net cash provided by operating activities was $ 508.5 million , $ 331.1 million , and $ 437.0 million in 2018 , 2017 , and 2016 , respectively . operating cash flows are primarily derived from providing air transportation to customers . the vast majority of tickets are purchased in advance of when travel is provided , and in some cases , several months before the anticipated travel date . operating cash outflows are related to the recurring expenses of the airline operations . the operating cash flows for 2018 , 2017 , and 2016 were impacted primarily by our results of operations , adjusted for non-cash items as well as changes in the air traffic liability , accounts receivables and other asset and liabilities , net .
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 Suspicious Activity Report : 2017 passenger revenue passenger revenue was $ 2.60 billion and $ 2.49 billion for the years ended december 31 , 2018 and 2017 , respectively . details of these changes are described in the table below : replace_table_token_6_th domestic revenue increased by $ 58.9 million driven by a 2.7 % increase in passengers flown on our domestic routes , partially offset by a 1.2 % decline in average fares . unit revenue declines primarily resulted from capacity growth in the region , specifically between hawai ' i and north america , combined with a reduction in travel attributed to weather-related events impacting the state of hawai ' i . international revenue increased by $ 57.0 million for the year ended december 31 , 2018 as compared to the prior year period driven by a combination of increased passenger counts and average fares , which outpaced capacity growth . in 2017 , we completed the upgrade of our first class cabin and extra comfort seating products on our a330 aircraft , which are driving improvements in profitability and unit revenue growth . during the year we expanded our operations and now have direct routes between maui , hawai ' i and portland , oregon ( january 2018 ) , kona , hawai ' i and los angeles , california ( march 2018 ) , lihue , hawai ' i and los angeles , california ( may 2018 ) , honolulu , hawai ' i and long beach , california ( may 2018 ) , maui , hawai ' i and san diego , california ( june 2018 ) , and lihue , hawai ' i and oakland , california ( july 2018 - expansion to daily service ) . in october 2018 , we suspended our thrice-weekly nonstop service between honolulu , hawai ' i and beijing , china . in september 2018 , we announced our new direct route between honolulu , hawai ' i and boston , massachusetts , which will commence in april 2019. during the first quarter of 2019 , we will have retired our last boeing 767-300 aircraft , completing the transition to our a321 aircraft , allowing for optimization of our products and better capacity management . other operating revenue other operating revenue increased by $ 46.3 million , or 24.6 % , in 2018 , as compared to 2017 , primarily due to an increase in loyalty program revenue of $ 31.8 million related to brand usage associated with our co-brand credit card partnership with barclays , which was amended in the first quarter of 2018. refer to note 1 in the consolidated financial statements for additional information . cargo revenue was up $ 9.0 million as a result of increased freight volumes and the introduction of our inter-island cargo freighter operation in the fourth quarter of 2018. operating expenses during the year ended december 31 , 2018 , total operating expense increased $ 311.9 million or 14.1 % to $ 2.5 billion as compared to the same period in 2017. the largest components of our operating expenses are wages and benefits provided to our 27 employees and aircraft fuel ( including taxes and delivery ) . increases ( decreases ) in operating expenses are detailed below . replace_table_token_7_th aircraft fuel the price and availability of aircraft fuel is volatile due to global economic and geopolitical factors that we can neither control nor accurately predict . the increases in aircraft fuel expense are illustrated in the following table : replace_table_token_8_th the increase in fuel expense from 2017 to 2018 is due to an increase in average fuel price per gallon and increased fuel consumption driven by capacity growth . we believe economic fuel expense is the best measure of the effect of fuel prices on our business as it most closely approximates the net cash outflow associated with the purchase of fuel for our operations and is consistent with how management manages our business and assesses our operating performance . we define economic fuel expense as gaap fuel expense plus ( gains ) /losses realized through actual cash ( receipts ) /payments received from or paid to hedge counterparties for fuel hedge derivative contracts settled in the period inclusive of costs related to hedging premiums . economic fuel expense is calculated as follows : replace_table_token_9_th 28 see item 7a , quantitative and qualitative disclosures about market risk , for additional discussion of our jet fuel costs and related derivative program . wages and benefits wages and benefits expense increased by $ 51.7 million , or 8.2 % , in 2018 , as compared to 2017 , primarily driven by increased overall headcount ( up 8.8 % in 2018 ) . the higher wages and benefits expenses also reflected an increase in cost incurred for training to prepare for the induction of our a321neo fleet which entered service during 2018. maintenance materials and repairs maintenance materials and repairs increased $ 20.2 million , or 9.2 % , in 2018 , as compared to 2017. on a per asm basis , maintenance , materials , and repairs expense increased 2.9 % as compared to the prior year , primarily due to an increase in the number of airframe and engine maintenance events , higher cost of materials for aging aircraft , and an increase in rates on our power by hour contract . aircraft and passenger servicing aircraft and passenger servicing expenses increased $ 12.9 million , or 8.9 % , in 2018 , as compared to 2017 , resulting from higher food and beverage expenses attributed to increased passenger counts ( up 2.9 % in 2018 ) and an increase in ground handling services reflective of increased operations in domestic and international markets . story_separator_special_tag loss ( gain ) on sale of aircraft is the result of adjustments to the final purchase price for three of our boeing 767-300 aircraft included in a forward sale agreement we entered into in january 2018 and described below . during the twelve months ended december 31 , 2018 , we recorded a loss of $ 0.3 million . 2016 special items an impairment analysis and ultimate charge was triggered by the decision in the fourth quarter of 2016 to exit our boeing 767-300 fleet in 2018. we estimated the fair value of the owned boeing 767-300 fleet assets using third party pricing information and quotes from potential buyers , which resulted in a $ 49.4 million impairment charge . in 2016 , we accrued $ 34.0 million associated with the tentative agreement with alpa related to past service ( prior to january 1 , 2017 ) and also elected to pay a $ 4.8 million profit sharing bonus payment to other labor groups related to prior period service . in connection with the decision to exit the boeing 767-300 fleet , we negotiated a termination of our boeing 767-300 maintenance agreement and recorded a $ 21.0 million charge related to the amount paid to terminate the contract . 2017 special items in august 2017 , we terminated the hawaiian airlines , inc. salaried & iam merged pension plan ( the merged plan ) and settled a portion of our pilots ' other post-retirement medical plan liability . in connection with the reduction of these liabilities we recorded one-time other nonoperating special charges of $ 35.2 million related to the merged plan termination and $ 10.4 million related to the other post-retirement ( opeb ) medical plan partial settlement . in april 2017 , we executed a sale leaseback transaction with an independent third party for three boeing 767-300 aircraft . the lease terms for the three aircraft commenced in april 2017 and end between november 2018 and january 2019. during the twelve months ended december 31 , 2017 , we recorded a loss on sale of aircraft of $ 4.8 million . in february 2017 , we reached a tentative agreement with alpa , covering our pilots . in march 2017 , we received notice from alpa that the agreement was ratified by alpa 's members . the agreement became effective april 1 , 2017 and has a term of 63 months . the agreement includes , among other various benefits , a pay adjustment and ratification bonus computed based on previous service . during the twelve months ended december 31 , 2017 , we expensed $ 18.7 million primarily related to a one-time payment to reduce our future 401k employer contribution for certain pilot groups , which is not recoverable once paid . 2018 contract terminations expense during the twelve months ended december 31 , 2018 , we terminated two contracts which incurred a total of $ 35.3 million in contract terminations expense . the transactions are described below : ◦ in february 2018 , we exercised our right to terminate our aircraft purchase agreement with airbus for six airbus a330-800neo aircraft and the purchase rights for an additional six airbus a330-800neo aircraft . to terminate the purchase agreement , we were obligated to repay airbus for concessions received relating to a prior firm order , training credits , as well as forfeit the pre-delivery progress payments made towards the flight equipment . we recorded a contract terminations expense to reflect the termination penalty in our consolidated statements of operations . 36 ◦ in january 2018 , we entered into a transaction with our lessor to early terminate and purchase three boeing 767-300 aircraft leases and concurrently entered into a forward sale agreement for the same three boeing 767-300 aircraft , including two pratt & whitney 4060 engines for each aircraft . these aircraft were previously accounted for as operating leases . in order to exit the lease and purchase the aircraft , we agreed to pay a total of $ 67.1 million ( net of all deposits ) of which a portion was expensed immediately and recognized as a contract termination fee . the expensed amount represents the total purchase price amount over fair value of the aircraft purchased as of the date of the transaction . we believe that excluding such special items helps investors analyze our operational performance and compare our results to other airlines in the periods presented below . replace_table_token_17_th operating costs per available seat mile ( casm ) we have separately listed in the table below our fuel costs per asm and non-gaap unit costs , excluding fuel and special items . these amounts are included in casm , but for internal purposes we consistently use cost metrics that exclude fuel and special items ( if applicable ) to measure and monitor its costs . 37 casm and casm , excluding fuel , loss on sale of aircraft , contract terminations expense , and special items , are summarized in the table below : replace_table_token_18_th critical accounting policies and estimates the discussion and analysis of our financial condition and results of operations are based upon financial statements that have been prepared in accordance with u.s. generally accepted accounting principles . the preparation of these financial statements requires management to make estimates and judgments that affect the reported amount of assets and liabilities , revenue and expenses , and related disclosure of contingent assets and liabilities as of the date of the financial statements . actual results could differ from those estimates . critical accounting policies and estimates are defined as those accounting policies and accounting estimates that are reflective of significant judgments and uncertainties , and that potentially result in materially different results under different assumptions and conditions . our most critical accounting policies and estimates are described below . see the summary of significant accounting policies included in note 1 to the consolidated financial statements for additional discussion of the

