Executive Order 6591 Directing the Army to Fly the Mail.
Whereas by an order of the Postmaster General of the United States all domestic air mail contracts for carrying the mails have been annulled; and
Whereas the public interest requires that air mail service continue to be afforded and the cancellation of said contracts has created an emergency in this respect;
Now, Therefore I, Franklin D. Roosevelt, President of the United States, under and by virtue of the authority in me vested, do hereby order and direct that the Postmaster General, Secretary of War, and Secretary of Commerce, together with other officers of their respective Departments, cooperate to the end that necessary air mail service be afforded.
It is further ordered and directed that the Secretary of War place at the disposal of the Postmaster General such airplanes, landing fields, pilots, and other employees and equipment of the Army of the United States needed or required for the transportation of mail, during the present emergency, by air over routes and schedules prescribed by the Postmaster General.
Franklin D. Roosevelt, Executive Order 6591 Directing the Army to Fly the Mail. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/208372