45,000 feet is highest an airliner goes today

Q What is the highest altitude an airplane can fly? — Churachandpur Manipur A The

highest commercial airliner altitude was 60,000 feet by Concorde. The highest military air-breathing engine airplane was the SR-71 — about 90,000 feet. The highest airliner flying today reaches 45,000 feet. The highest business jet flying today reaches 51,000 feet. Q At what altitude would the wings of an aircraft lose effectiveness? — Kevin T. A It

depends on the wing and how much air can be kept flowing over it. The SR-71 routinely flew over 80,000 feet, but it was a very special wing. The space shuttle began encountering “usable” air around 100,000 feet during descent; it, too, was a very special wing and vehicle. Q If a plane went past 100,000 feet, what would happen to it? — Bob, Georgia State A No

commercial or business airplane flying today can exceed 100,000 feet. Special rocket-powered airplanes can fly over 100,000 feet to gather data, but they are specially designed for it. Q Much beyond the certified ceiling, can an aircraft maintain altitude? — Stealth, Canada A During

certification testing, airplanes are flown above the certified ceiling, but the performance is limited. The answer is that aircraft may be able to maintain altitude above service ceiling, depending on the weight and temperature, but not very much above it. Q At cruising altitude for a 767, what is the cabin pressure vs. altitude? — Cary, Honolulu A The cabin pressure is maintained at 8,000 feet when the 767 operates at its service ceiling of 43,000 feet. Q What’s the service ceiling for the Boeing 757? — Buzz, Delray Beach, Fla. A It’s 42,000 feet and is limited by the pressurization and the ability to descend to a low altitude should it be necessary. Have a question about flying? Send it to travel@usatoday.com.