| http://www.w3.org/ns/prov#value | - 0 The B52 regularly cruises above 70,000 feet because it is powered by The X15 was able to reach altitudes of 350,000 feet, but these were Why do airplanes fly at such high altitudes? : Airliners are usually rated below 40,000 feet, so expect most of those There???s still air at 70,000 feet, so it???s still possible to fly, especially if you are below 50,000 feet because their engines cannot get e
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