((a)) In this section, buying a passenger motor vehicle or aircraft includes a transfer of the vehicle or aircraft between agencies.

((b)) An appropriation may be expended to buy or lease passenger motor vehicles only—

((1)) for the use of—

((A)) the President;

((B)) the secretaries to the President; or

((C)) the heads of executive departments listed in ; or

((2)) as specifically provided by law.

((c))

((1)) Except as specifically provided by law, an agency may use an appropriation to buy a passenger motor vehicle (except a bus or ambulance) only at a total cost (except costs required only for transportation) that—

((A)) includes the price of systems and equipment the Administrator of General Services decides is incorporated customarily in standard passenger motor vehicles completely equipped for ordinary operation;

((B)) includes the value of a vehicle used in exchange;

((C)) is not more than the maximum price established by the agency having authority under law to establish a maximum price; and

((D)) is not more than the amount specified in a law.

((2)) Additional systems and equipment may be bought for a passenger motor vehicle if the Administrator decides the purchase is appropriate. The price of additional systems or equipment is not included in deciding whether the cost of the vehicle is within a maximum price specified in a law.

((d)) An appropriation (except an appropriation for the armed forces) is available to buy, maintain, or operate an aircraft only if the appropriation specifically authorizes the purchase, maintenance, or operation.

((e)) This section does not apply to—

((1)) buying, maintaining, and repairing passenger motor vehicles by the United States Capitol Police;

((2)) buying, maintaining, and repairing vehicles necessary to carry out projects to improve, preserve, and protect rivers and harbors; or

((3)) leasing, maintaining, repairing, or operating motor passenger vehicles necessary in the field work of the Department of Agriculture.