After 32 years of wondering if anything other than the handful of "theme" cover versions of "Airport '77" may have existed I found this on a forum, which will remain anonymous as I don't want the poster flooded with requests as desperate as mine was. In the end I elicited the help of the forum founder who relayed: "Once he gets his LPs in a digital format, he will reach out to people." (hopefully myself included).
Anyway - the post went like this (it was in relation to some fan-art cover mockups that had somehow found their way to a vinyl forum): "I have a test pressing acetate with 6 songs from Airport '77. No frills, center label hand written. Has theme/end credits and 4 of incidental background music tracks. Plain white cover. Are either of these the proposed cover art if they hadn't scrapped the soundtrack?? Anyone??"
No other information was forthcoming... sounds very much like what may have been Side 2 of a proposed soundtrack album.
Fingers crossed and will advise as I hear anything.
That is awesome! I had no idea they even considered an LP release of '77.