Any lease under shall be for a period not to exceed twenty years, subject to renewal for like periods upon agreement of the Secretary of the Interior and the lessee. Any such lease shall be subject to the following conditions:

((a)) That an annual rental of such sum as the Secretary of the Interior may fix for the use of the lands shall be paid to the United States.

((b)) That the lessee shall maintain the lands in such condition, and provide for the furnishing of such facilities, service, fuel, and other supplies, as are necessary to make the lands available for public use as an airport of a rating which may be prescribed by the Administrator of the Federal Aviation Agency.

((c)) That the lessee shall make reasonable regulations to govern the use of the airport, but such regulations shall take effect only upon approval by the Administrator of the Federal Aviation Agency.

((d)) That all departments and agencies of the United States operating aircraft (1) shall have free and unrestricted use of the airport, and (2) with the approval of the Secretary of the Interior, shall have the right to erect and install therein such structures and improvements as the heads of such departments and agencies deem advisable, including facilities for maintaining supplies of fuel, oil, and other materials for operating aircraft.

((e)) That whenever the President may deem it necessary for military purposes, the Secretary of the Army may assume full control of the airport.