Explorer II was a crewed U.S. high-altitude balloon that was launched on November 11, 1935, and reached a record altitude of 22,066 m (72,395 ft). Launched at 8:00 am from the Stratobowl in South Dakota, the helium balloon carried a two-man crew consisting of U. S. Army Air Corps Captains Albert W. Stevens and Orvil A. Anderson inside a sealed, spherical cabin. The crew landed safely near White Lake, South Dakota, at 4:13 pm and both were acclaimed as national heroes. Scientific instruments carried on the gondola returned useful information about the stratosphere. The mission was funded by the membership of the National Geographic Society.

This listing of flight altitude records are the records set for the highest aeronautical flights conducted in the atmosphere, set since the age of ballooning.