They froze victims to research hypothermia, placed them in compression chambers to test the effects of high-altitude flight.

SS1 became the world's first private spaceship with a series of high-altitude flights in 2004.

Pressure suits were mandatory on all high-altitude or low-orbital flights.

Incidents when airplanes come too close together are automatically recorded by a computer for aircraft in high-altitude flight.

Post's work showed sustained high-altitude flight was possible, but pressure suits were uncomfortable and restrictive.

Douglas Pobjoy then moved on to designing de-icing equipment for high-altitude flights.

He went on to help develop life-support systems for high-altitude flight and space travel.

In general, birds have physiological features that are advantageous for high-altitude flight.

Their aim was to reach a height of 30 kilometres, beating the world record for high-altitude flight.

After this, there were no more high-altitude flights in the 1930s.