Harry Truman actually said...
By virtue of and pursuant to the authority vested in me by section 4 of the Air Commerce Act of 1926 (44 Stat. 570), the airspace above the three following-described portions of the United States is hereby reserved and set apart for national defense and other governmental purposes as airspace reservations within which no personal shall navigate an aircraft except in the interest of national defense or by authority of the United States Atomic Energy Commission:
01/16/1948