Ironically, that’s about the only part of the song that is ironic 
That’s two John Denver songs about flying posted now, counting “Leaving on a Jet Plane” I posted in the OP. Ironic, considering…
Ooh, just thought of another one-- not so muhc about passenger flight as air freight, let’s say…
When two low-flying aeroplanes, ‘bout a hundred feet high
Dropped a bunch o’ bales o’ somethin’, some hit me in the eye…