; reserve plant and Government and contractor-owned equipment layaway; and other expenses necessary for the foregoing purposes including rents and transportation of things, $17,118,921,000 (increased by $65,000,000), to remain available for obligation until September 30, 2021. Missile procurement, air force For construction, procurement, and modification of missiles, rockets, and related equipment, including spare parts and accessories therefor; ground handling equipment, and training devices; expansion of public and private plants, Government-owned equipment and installation thereof in such plants, erection of structures, and acquisition of land, for the foregoing purposes, and such lands and interests therein, may be acquired, and construction prosecuted thereon prior to approval of title; reserve plant and Government and contractor-owned equipment layaway; and other expenses necessary for the foregoing purposes including rents and transportation of things, $2,591,982,000, to remain available for obligation until September 30, 2021. Space procurement, air force For construction, procurement, and modification of spacecraft, rockets, and related equipment, including spare parts and accessories therefor; ground handling equipment, and training devices; expansion of public and private plants, Government-owned equipment and installation thereof in such plants, erection of structures, and acquisition of land, for the foregoing purposes, and such lands and interests therein, may be acquired, and construction prosecuted thereon prior to approval of title; reserve plant and Government and contractor-owned equipment layaway; and other expenses necessary for the foregoing purposes including rents and transportation of things, $2,388,642,000, to remain available for obligation until September 30, 2021. Procurement of ammunition, air force For construction, procurement, production, and modification of ammunition, and accessories therefor; specialized equipment and training devices