49 U.S.C. § 40107

1. (a)The President may transfer to the Administrator of the Federal Aviation Administration a duty, power, activity, or facility of a department, agency, or instrumentality of the executive branch of the United States Government, or an officer or unit of a department, agency, or instrumentality of the executive branch, related primarily to selecting, developing, testing, evaluating, establishing, operating, or maintaining a system, procedure, facility, or device for safe and efficient air navigation and air traffic control. In making a transfer, the President may transfer records and property and make officers and employees from the department, agency, instrumentality, or unit available to the Administrator.
2. (b)If war occurs, the President by executive order may transfer to the Secretary of Defense a duty, power, activity, or facility of the Administrator. In making the transfer, the President may transfer records, property, officers, and employees of the Administration to the Department of Defense.