Executive Order 6023—Air-Space Reservation, District of Columbia
By authority of the provisions of section 4 of the Air Commerce Act of 1926 (44 Stat. 568, 570), the air space over the District of Columbia is hereby designated as a prohibited area from 9 a. m. to 5 p. m., on March 4, 1933, for public-safety purposes.
Between the time above specified, no aircraft shall be navigated through the air space over the District of Columbia except such aircraft as may be specifically permitted by the Secretary of Commerce, between such time and over such places as the Secretary of Commerce in his discretion may determine.
The White House,
February 11, 1933.
Herbert Hoover, Executive Order 6023—Air-Space Reservation, District of Columbia Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/361575