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Highest altitude in horizontal flight

Highest altitude in horizontal flight
Who
Capt. Robert C. Helt , Maj. Larry A. Elliot , Lockheed SR-71A Blackbird
What
25,929.031 metre(s)
Where
United States (Beale Air Force Base,)
When
28 July 1976

USAF Capt. Robert C. Helt (pilot) and USAF Maj. Larry A. Elliott (RSO) reached an altitude of 25,929.031 m (85,068.997 ft) in sustained horizontal flight in a Lockheed SR-71A Blackbird at Beale Air Force Base, California, USA, on 28 July 1976.

For comparison, a Boeing 747 cruises at an altitude of 10,000 m. (35,000 ft.).

This is not an official FAI record. See 'Highest altitude by an aircraft (official FAI)'.