the company 's airlines have been providing passenger and cargo airlift services to the u.s. dod since the mid 1990 's . contracts with the ustc are typically for a one-year period , however , the current passenger international charter contract has a two-year term with option periods , at the election of the dod , through september 2024 and the contract with ati to provide combi aircraft operations , runs through december 2021. due to the acquisition of oai , the dod comprises a larger portion of our 2020 and 2019 consolidated revenues compared to previous years . revenues from our commercial arrangements with asi comprised approximately 30 % , 23 % and 27 % of our consolidated revenues during the years ended december 31 , 2020 , 2019 and 2018 , respectively . on march 8 , 2016 , we entered into an air transportation services agreement ( as amended , the “ atsa ” ) with asi pursuant to which we lease boeing 767 freighter aircraft to asi , operate the aircraft via our airline subsidiaries and provide ground 30 handling services by our subsidiary , lgstx . under the atsa , we operate aircraft based on pre-defined fees scaled for the number of aircraft hours flown , aircraft scheduled and flight crews provided to asi for its network . the operating term of the atsa runs through march of 2024 and is thereafter subject to renewal provisions . the aircraft lease terms range from 5 to 10 years . for more information about the atsa , including its amendments , see item 1 of this report . the table below summarizes aircraft lease placements and commitments with amazon as of december 31 , 2020. replace_table_token_4_th in conjunction with the execution of the atsa and its amendments , the company and amazon entered into an investment agreement and a stockholders agreement on march 8 , 2016 ( the 2016 investment agreement ) and a second investment agreement on december 20 , 2018 ( the 2018 investment agreement ) . pursuant to these investment agreements , the company issued warrants to amazon in conjunction with aircraft leases . through the 2016 and 2018 investment agreements and the exercise of the warrants granted thereunder , amazon could potentially own approximately 39.9 % of the company if all the issued and issuable warrants vest and are settled in full with cash . our accounting for the warrants issued to amazon has been determined in accordance with the financial reporting guidance for financial instruments . the fair value of the warrants issued or issuable to amazon are recorded as a lease incentive asset and are amortized against revenues over the duration of the aircraft leases . the warrants are accounted for as financial instruments , and accordingly , the fair value of the outstanding warrants are measured and classified in liabilities at the end of each reporting period . the company 's earnings are impacted by the fair value re-measurement of the amazon warrants classified in liabilities at the end of each reporting period , customer incentive amortization and the related income tax effects . for income tax calculations , the value and timing of related tax deductions will differ from the guidance described below for financial reporting . for additional information about the warrants , see note d to the accompanying consolidated financial statements in this report . dhl accounted for 12 % , 14 % and 26 % of the company 's consolidated revenues , excluding directly reimbursed revenues , during the years ended december 31 , 2020 , 2019 and 2018 , respectively . under a cmi agreement with dhl , abx operates and maintains aircraft based on pre-defined fees scaled for the number of aircraft hours flown , aircraft scheduled and flight crews provided to dhl for its network . under the pricing structure of the cmi agreement , abx is responsible for complying with faa airworthiness directives , the cost of boeing 767 airframe maintenance and certain engine maintenance events for the aircraft leased to dhl that it operates . as of december 31 , 2020 , the company , through cam , leased 14 boeing 767 aircraft to dhl comprised of seven boeing 767-200 aircraft and seven boeing 767-300 aircraft , expiring between 2021 and 2024. eight of the 14 boeing 767 aircraft were being operated by the company 's airlines for dhl . we also operated four cam-owned boeing 757 aircraft under other operating arrangements with dhl during 2019 and the first half of 2020. during 2020 , dhl terminated operating agreements for three of the boeing 757 aircraft . the decline in the percentage of revenues from dhl primarily reflects the removal of the boeing 757 operations and increased revenues from other customers compared to last year . 31 results of operations revenue and earnings summary external customer revenues from continuing operations increased by $ 118.4 million , or 8 % , to $ 1,570.6 million during 2020 compared to 2019. customer revenues increased in 2020 for contracted airline services , charter flights , aircraft leasing and aviation fuel sales , compared to the previous year periods . beginning in late february 2020 , our revenues were disrupted due to the covid-19 pandemic . the dod and other customers began canceling scheduled passenger flights as a result of the pandemic . the decline in revenues from these cancellations was offset by an increase in flying for our customers ' package delivery networks and charter flight operations during 2020. revenues for 2018 were $ 892.3 million and included only a few weeks of revenue for oai which was acquired on november 9 , 2018. the consolidated net earnings from continuing operations were $ 25.1 million for 2020 compared to $ 60.0 million for 2019 and $ 67.9 million for 2018. the pre-tax earnings from continuing operations were $ 41.4 million for 2020 compared to $ 71.6 million for 2019 and $ 87.5 million for story_separator_special_tag expenses from continuing operations salaries , wages and benefits expense increased $ 85.4 million , or 20 % during 2020 compared to 2019 driven by higher employee headcount for flight operations , maintenance operations and package sorting services . the total headcount increased 20 % as of december 31 , 2020 compared to december 31 , 2019. the increases during 2020 include additional flight crewmembers , aircraft maintenance technicians and other personnel to support increased block hours . depreciation and amortization expense increased $ 20.5 million during 2020 compared to 2019. the increase reflects incremental depreciation for eleven boeing 767-300 aircraft and additional aircraft engines added to the operating fleet since the beginning of 2020 , as well as capitalized heavy maintenance and navigation technology upgrades . we expect depreciation expense to increase during future periods in conjunction with our fleet expansion and capital spending plans . maintenance , materials and repairs expense increased by $ 9.2 million during 2020 compared to 2019. increased maintenance expense for 2020 was driven by increased flight hours and higher costs for unscheduled engine repairs at our airlines . the aircraft maintenance and material expenses can vary among periods due to the number of maintenance events and the scope of airframe checks that are performed . 37 fuel expense decreased by $ 6.7 million during 2020 compared to 2019. fuel expense includes the cost of fuel to operate dod charters , fuel used to position aircraft for service and for maintenance purposes , as well as the cost of fuel sales . fuel expense decreased during 2020 compared to 2019 due to lower prices for aviation fuel during the pandemic . contracted ground and aviation services expense includes navigational services , aircraft and cargo handling services , baggage handling services and other airport services . contracted ground and aviation services decreased $ 0.5 million during 2020 compared to 2019. since mid-2019 , certain customers chose to in-source some ground services that we had been performing on their behalf . travel expense decreased by $ 13.6 million during 2020 compared to 2019. the decrease in travel expense was due to less employee travel and the lower costs of air travel during the pandemic . landing and ramp expense , which includes the cost of deicing chemicals , increased by $ 1.3 million during 2020 compared to 2019 , driven by increased block hours and network locations . rent expense increased by $ 3.3 million during 2020 compared to 2019 due to an additional aircraft partially offset by lower facility rents during 2020. insurance expense increased by $ 2.6 million during 2020 compared to 2019. aircraft fleet insurance has increased due to additional aircraft operations and higher insurance rates during 2020 compared to 2019. other operating expenses decreased by $ 4.0 million during 2020 compared to 2019. other operating expenses include professional fees , employee training , utilities , commission expense to our craf team for dod revenues and other expenses . asset impairment charges were recorded during the second quarter of 2020 , in conjunction with management 's decision to retire four boeing 757 freighter aircraft . three of the 757 airframes have been removed from service and are available for sale . one remains in service through the first quarter of 2021. impairment charges totaling $ 39.1 million were recorded , primarily reflecting the fair value of these assets as well as other surplus engines and parts . operating results included a pre-tax contra expense of $ 47.2 million during 2020 to recognize grants received from the u.s. government under the cares act . for additional information about the cares act grants , see note i of the unaudited condensed consolidated financial statements included in this report . non operating income , adjustments and expense s interest expense decreased by $ 3.8 million during 2020 compared to 2019. interest expense during 2020 decreased compared to the previous year due to lower interest rates on our borrowings under the senior credit agreement and lower debt balances outstanding during the year . the company recorded unrealized pre-tax losses on financial instruments re-measurements of $ 100.8 million during the year ended december 31 , 2020 , compared to $ 12.3 million for 2019. the gains and losses include the results of re-valuing , as of december 31 , 2020 and 2019 , the fair value of the stock warrants granted to amazon . generally , the warrant value increases or decreases with corresponding increases or decreases in the atsg share price during the measurement period . warrant losses for 2020 reflect a 34 % increase in the traded price of atsg shares . additionally , the value of certain warrants depend partially on the probability that warrants will vest upon the execution of aircraft leases . increases in the traded value of atsg shares and increases in the probability of vested warrants each result in an increase to the warrant value and resulted in warrant losses recorded to financial instruments for 2020. non service components of retiree benefits were a net loss of $ 12.0 million for 2020 compared to a net gain of $ 9.4 million for 2019. the non service component gain and losses of retiree benefits are actuarially determined and include the amortization of unrecognized gain and loss stemming from changes in assumptions regarding discount rates , expected investment returns and other retirement plan assumptions . non service components of retiree benefits can vary significantly from one year to the next based on investment results and changes in discount rates used to account for defined benefit retirement plans . income tax expense from earnings from continuing operations decreased $ 4.7 million for 2020 compared to 2019. income taxes included deferred income tax effects for the gains and losses from warrant re-measurements and the amortization of the customer incentive . the income tax effects of the warrant re-measurements and the 38 amortization of the customer incentive are different than the book expenses and benefits required

cash flows net cash generated from operating activities totaled $ 512.3 million , $ 396.9 million and $ 298.0 million in 2020 , 2019 and 2018 , respectively . improved cash flows generated from operating activities during 2020 and 2019 included additional aircraft leases to customers and increased operating levels of the acmi services segment . operating cash flows for 2020 include the receipt of $ 75.8 million of grant funds from the cares act . cash outlays for pension contributions were $ 10.8 million , $ 5.4 million and $ 22.2 million in 2020 , 2019 and 2018 , respectively . capital spending levels were primarily the result of aircraft modification costs and the acquisition of aircraft for freighter modification . cash payments for capital expenditures were $ 510.4 million , $ 453.5 million and $ 292.9 million in 2020 , 2019 and 2018 , respectively . capital expenditures in 2020 included $ 353.4 million for the acquisition of eleven boeing 767-300 aircraft and freighter modification costs ; $ 76.0 million for required heavy maintenance ; and $ 81.0 million for other equipment , including purchases of aircraft engines and rotables . capital expenditures in 2019 included $ 328.0 million for the acquisition of eleven boeing 767-300 aircraft and freighter modification costs ; $ 76.1 million for required heavy maintenance ; and $ 49.4 million for other equipment , including the purchases of aircraft engines and rotables . our capital expenditures in 2018 included $ 197.1 million for the acquisition of eight boeing 767-300 aircraft and freighter modification costs ; $ 61.7 million for required heavy maintenance ; and $ 34.1 million for other equipment , including purchases of aircraft engines and rotables . cash proceeds of $ 24.6 million , $ 10.8 million and $ 17.6 million were received in 2020 , 2019 and 2018 , respectively , for the sale of aircraft engines and airframes . during 2020 , 2019 and 2018 , we spent $ 13.3 million , $ 24.4 million and $ 866.6 million , respectively , for acquisitions and investments in other businesses .


 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.
     ```cash flows net cash generated from operating activities totaled $ 512.3 million , $ 396.9 million and $ 298.0 million in 2020 , 2019 and 2018 , respectively . improved cash flows generated from operating activities during 2020 and 2019 included additional aircraft leases to customers and increased operating levels of the acmi services segment . operating cash flows for 2020 include the receipt of $ 75.8 million of grant funds from the cares act . cash outlays for pension contributions were $ 10.8 million , $ 5.4 million and $ 22.2 million in 2020 , 2019 and 2018 , respectively . capital spending levels were primarily the result of aircraft modification costs and the acquisition of aircraft for freighter modification . cash payments for capital expenditures were $ 510.4 million , $ 453.5 million and $ 292.9 million in 2020 , 2019 and 2018 , respectively . capital expenditures in 2020 included $ 353.4 million for the acquisition of eleven boeing 767-300 aircraft and freighter modification costs ; $ 76.0 million for required heavy maintenance ; and $ 81.0 million for other equipment , including purchases of aircraft engines and rotables . capital expenditures in 2019 included $ 328.0 million for the acquisition of eleven boeing 767-300 aircraft and freighter modification costs ; $ 76.1 million for required heavy maintenance ; and $ 49.4 million for other equipment , including the purchases of aircraft engines and rotables . our capital expenditures in 2018 included $ 197.1 million for the acquisition of eight boeing 767-300 aircraft and freighter modification costs ; $ 61.7 million for required heavy maintenance ; and $ 34.1 million for other equipment , including purchases of aircraft engines and rotables . cash proceeds of $ 24.6 million , $ 10.8 million and $ 17.6 million were received in 2020 , 2019 and 2018 , respectively , for the sale of aircraft engines and airframes . during 2020 , 2019 and 2018 , we spent $ 13.3 million , $ 24.4 million and $ 866.6 million , respectively , for acquisitions and investments in other businesses .
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 Suspicious Activity Report : the company 's airlines have been providing passenger and cargo airlift services to the u.s. dod since the mid 1990 's . contracts with the ustc are typically for a one-year period , however , the current passenger international charter contract has a two-year term with option periods , at the election of the dod , through september 2024 and the contract with ati to provide combi aircraft operations , runs through december 2021. due to the acquisition of oai , the dod comprises a larger portion of our 2020 and 2019 consolidated revenues compared to previous years . revenues from our commercial arrangements with asi comprised approximately 30 % , 23 % and 27 % of our consolidated revenues during the years ended december 31 , 2020 , 2019 and 2018 , respectively . on march 8 , 2016 , we entered into an air transportation services agreement ( as amended , the “ atsa ” ) with asi pursuant to which we lease boeing 767 freighter aircraft to asi , operate the aircraft via our airline subsidiaries and provide ground 30 handling services by our subsidiary , lgstx . under the atsa , we operate aircraft based on pre-defined fees scaled for the number of aircraft hours flown , aircraft scheduled and flight crews provided to asi for its network . the operating term of the atsa runs through march of 2024 and is thereafter subject to renewal provisions . the aircraft lease terms range from 5 to 10 years . for more information about the atsa , including its amendments , see item 1 of this report . the table below summarizes aircraft lease placements and commitments with amazon as of december 31 , 2020. replace_table_token_4_th in conjunction with the execution of the atsa and its amendments , the company and amazon entered into an investment agreement and a stockholders agreement on march 8 , 2016 ( the 2016 investment agreement ) and a second investment agreement on december 20 , 2018 ( the 2018 investment agreement ) . pursuant to these investment agreements , the company issued warrants to amazon in conjunction with aircraft leases . through the 2016 and 2018 investment agreements and the exercise of the warrants granted thereunder , amazon could potentially own approximately 39.9 % of the company if all the issued and issuable warrants vest and are settled in full with cash . our accounting for the warrants issued to amazon has been determined in accordance with the financial reporting guidance for financial instruments . the fair value of the warrants issued or issuable to amazon are recorded as a lease incentive asset and are amortized against revenues over the duration of the aircraft leases . the warrants are accounted for as financial instruments , and accordingly , the fair value of the outstanding warrants are measured and classified in liabilities at the end of each reporting period . the company 's earnings are impacted by the fair value re-measurement of the amazon warrants classified in liabilities at the end of each reporting period , customer incentive amortization and the related income tax effects . for income tax calculations , the value and timing of related tax deductions will differ from the guidance described below for financial reporting . for additional information about the warrants , see note d to the accompanying consolidated financial statements in this report . dhl accounted for 12 % , 14 % and 26 % of the company 's consolidated revenues , excluding directly reimbursed revenues , during the years ended december 31 , 2020 , 2019 and 2018 , respectively . under a cmi agreement with dhl , abx operates and maintains aircraft based on pre-defined fees scaled for the number of aircraft hours flown , aircraft scheduled and flight crews provided to dhl for its network . under the pricing structure of the cmi agreement , abx is responsible for complying with faa airworthiness directives , the cost of boeing 767 airframe maintenance and certain engine maintenance events for the aircraft leased to dhl that it operates . as of december 31 , 2020 , the company , through cam , leased 14 boeing 767 aircraft to dhl comprised of seven boeing 767-200 aircraft and seven boeing 767-300 aircraft , expiring between 2021 and 2024. eight of the 14 boeing 767 aircraft were being operated by the company 's airlines for dhl . we also operated four cam-owned boeing 757 aircraft under other operating arrangements with dhl during 2019 and the first half of 2020. during 2020 , dhl terminated operating agreements for three of the boeing 757 aircraft . the decline in the percentage of revenues from dhl primarily reflects the removal of the boeing 757 operations and increased revenues from other customers compared to last year . 31 results of operations revenue and earnings summary external customer revenues from continuing operations increased by $ 118.4 million , or 8 % , to $ 1,570.6 million during 2020 compared to 2019. customer revenues increased in 2020 for contracted airline services , charter flights , aircraft leasing and aviation fuel sales , compared to the previous year periods . beginning in late february 2020 , our revenues were disrupted due to the covid-19 pandemic . the dod and other customers began canceling scheduled passenger flights as a result of the pandemic . the decline in revenues from these cancellations was offset by an increase in flying for our customers ' package delivery networks and charter flight operations during 2020. revenues for 2018 were $ 892.3 million and included only a few weeks of revenue for oai which was acquired on november 9 , 2018. the consolidated net earnings from continuing operations were $ 25.1 million for 2020 compared to $ 60.0 million for 2019 and $ 67.9 million for 2018. the pre-tax earnings from continuing operations were $ 41.4 million for 2020 compared to $ 71.6 million for 2019 and $ 87.5 million for story_separator_special_tag expenses from continuing operations salaries , wages and benefits expense increased $ 85.4 million , or 20 % during 2020 compared to 2019 driven by higher employee headcount for flight operations , maintenance operations and package sorting services . the total headcount increased 20 % as of december 31 , 2020 compared to december 31 , 2019. the increases during 2020 include additional flight crewmembers , aircraft maintenance technicians and other personnel to support increased block hours . depreciation and amortization expense increased $ 20.5 million during 2020 compared to 2019. the increase reflects incremental depreciation for eleven boeing 767-300 aircraft and additional aircraft engines added to the operating fleet since the beginning of 2020 , as well as capitalized heavy maintenance and navigation technology upgrades . we expect depreciation expense to increase during future periods in conjunction with our fleet expansion and capital spending plans . maintenance , materials and repairs expense increased by $ 9.2 million during 2020 compared to 2019. increased maintenance expense for 2020 was driven by increased flight hours and higher costs for unscheduled engine repairs at our airlines . the aircraft maintenance and material expenses can vary among periods due to the number of maintenance events and the scope of airframe checks that are performed . 37 fuel expense decreased by $ 6.7 million during 2020 compared to 2019. fuel expense includes the cost of fuel to operate dod charters , fuel used to position aircraft for service and for maintenance purposes , as well as the cost of fuel sales . fuel expense decreased during 2020 compared to 2019 due to lower prices for aviation fuel during the pandemic . contracted ground and aviation services expense includes navigational services , aircraft and cargo handling services , baggage handling services and other airport services . contracted ground and aviation services decreased $ 0.5 million during 2020 compared to 2019. since mid-2019 , certain customers chose to in-source some ground services that we had been performing on their behalf . travel expense decreased by $ 13.6 million during 2020 compared to 2019. the decrease in travel expense was due to less employee travel and the lower costs of air travel during the pandemic . landing and ramp expense , which includes the cost of deicing chemicals , increased by $ 1.3 million during 2020 compared to 2019 , driven by increased block hours and network locations . rent expense increased by $ 3.3 million during 2020 compared to 2019 due to an additional aircraft partially offset by lower facility rents during 2020. insurance expense increased by $ 2.6 million during 2020 compared to 2019. aircraft fleet insurance has increased due to additional aircraft operations and higher insurance rates during 2020 compared to 2019. other operating expenses decreased by $ 4.0 million during 2020 compared to 2019. other operating expenses include professional fees , employee training , utilities , commission expense to our craf team for dod revenues and other expenses . asset impairment charges were recorded during the second quarter of 2020 , in conjunction with management 's decision to retire four boeing 757 freighter aircraft . three of the 757 airframes have been removed from service and are available for sale . one remains in service through the first quarter of 2021. impairment charges totaling $ 39.1 million were recorded , primarily reflecting the fair value of these assets as well as other surplus engines and parts . operating results included a pre-tax contra expense of $ 47.2 million during 2020 to recognize grants received from the u.s. government under the cares act . for additional information about the cares act grants , see note i of the unaudited condensed consolidated financial statements included in this report . non operating income , adjustments and expense s interest expense decreased by $ 3.8 million during 2020 compared to 2019. interest expense during 2020 decreased compared to the previous year due to lower interest rates on our borrowings under the senior credit agreement and lower debt balances outstanding during the year . the company recorded unrealized pre-tax losses on financial instruments re-measurements of $ 100.8 million during the year ended december 31 , 2020 , compared to $ 12.3 million for 2019. the gains and losses include the results of re-valuing , as of december 31 , 2020 and 2019 , the fair value of the stock warrants granted to amazon . generally , the warrant value increases or decreases with corresponding increases or decreases in the atsg share price during the measurement period . warrant losses for 2020 reflect a 34 % increase in the traded price of atsg shares . additionally , the value of certain warrants depend partially on the probability that warrants will vest upon the execution of aircraft leases . increases in the traded value of atsg shares and increases in the probability of vested warrants each result in an increase to the warrant value and resulted in warrant losses recorded to financial instruments for 2020. non service components of retiree benefits were a net loss of $ 12.0 million for 2020 compared to a net gain of $ 9.4 million for 2019. the non service component gain and losses of retiree benefits are actuarially determined and include the amortization of unrecognized gain and loss stemming from changes in assumptions regarding discount rates , expected investment returns and other retirement plan assumptions . non service components of retiree benefits can vary significantly from one year to the next based on investment results and changes in discount rates used to account for defined benefit retirement plans . income tax expense from earnings from continuing operations decreased $ 4.7 million for 2020 compared to 2019. income taxes included deferred income tax effects for the gains and losses from warrant re-measurements and the amortization of the customer incentive . the income tax effects of the warrant re-measurements and the 38 amortization of the customer incentive are different than the book expenses and benefits required

