Yeah Denver was a fan. I recall he dedicated his live album or maybe a song from it to him.
That was I believe the source of his interest in flying, which interest ultimately resulted in his death.
If I recall correctly, his fatal mishap in an experimental airplane resulted from a poorly-located fuel valve, which would have allowed him to use fuel from a reserve tank when the man supply was exhausted.
As Dirty Harry famously said, "A man's got to know his limitations."
Kind of the exact opposite of the "human potential movement."