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FAA proposal: Supersonic airliners can fly over US cities if they’re quiet
FAA新规有望重开超音速商业飞行，条件是必须安静到听不见音爆。
New US rules would legalize quiet supersonic flights without the sonic boom.
FAA新规有望重开超音速商业飞行，条件是必须安静到听不见音爆。
New US rules would legalize quiet supersonic flights without the sonic boom.