• Later, I realized that the mission had to end in a let-down because the real barrier wasn't in the sky but in our knowledge and experience of supersonic flight.

    Chuck Yeager: Later, I realized that the mission had to end in a let-down because the real barrier wasn't in the sky but in our knowledge and experience of supersonic flight.
    Chuck Yeager (1986). “Yeager: An Autobiography”, Bantam