\fNOTES TO CONSOLIDATED FINANCIAL STATEMENTS OF AMERICAN AIRLINES GROUP INC . Commitments , Contingencies and Guarantees ( 2 ) Aircraft and Engine Purchase Commitment Under all of our aircraft and engine purchas ( approximately , in millions ) . agreements , our total future commitments as of December 31 2017 are expected to be as follows 2023 and Payments for aircraft commitments and certain Thereafter engines ! !) 1 826 5 730 8 2730 2858 5 432 5 93.7 64 These amounts are not of purchase deposits currently held by the manufacturers and include all commitments for regional aircraft American has granted a security interest in it billion as of December 31 2017 I in its purchase deposits with Boeing . Our purchase deposits held by all manufacturers totaled $1 2 ( b ) Operating Leases and Other We lease certain aircraft , engines and ground equipment , in addition to the majority of our ground facilities and terminal space . As of December 31 , 2017 , we had 421 aircraft under operating leases , with remaining terms ranging from three months to approximately 12 years Airports are utilized for flight operations under lease arrangements with the municipalities or agencies owning or controlling such asports Substantially all leases provide that the lessee must pay taxes , maintenance , insurance and certain other operating expenses applicable to the leased property . Some leases also include renewal and purchase options . in millions ) As of December 31 , 2017 , obligations under noncancellable operating leases for future minimum lease payments are as follows approximately 2023 and Thereafter Future minimum lease payments $ 2 195 5 1974 5 1,784 1 339 8 1 159 5 3 266 5 91 717 Mainline and regional rent expe rise , excluding landing fees , was $2 8 billion in each of 2017 2016 and 2015 . Additionally , we have purchase commitments related to jet fuel , facility construction projects and information technology support as follows ( approximately ) : 52 0 billion in 2018 , $1 4 billion in 2019 , $890 million in 2020 and $950 million in 2021 . ( C ) Capacity Purchase Agreements with Third Party Regional Carriers American has capacity purchase agreements with third -party regional carriers . The capacity purchase agreements provide that all revenues including passenger , in-flight , ancillary , mail and freight revenues , go to American . In return , American agrees to pay predetermined foes to these airlines for operating an agreed- upon number of aircraft , without regard to the number of passengers on board . In addition , these agreements provide that American reimburses 100% of certain variable costs , such as airport landing fees and passenger liability insurance . American controls marketing , scheduling ticketing pricing and seal inventories As of December 31 2017 , American's capacity purchase agreements with third party regional carriers had expiration dates ranging from 2018 to 2027 with rights of American to extend the respective terms of certain agreements . See Part 1 , Item 2 Properties for unaudited Information on the aircraft operated by third- party regional carriers under such capacity purchase agreements