Why were there optical sound trailers?!!

[Osi Osgood]

I just put up one on ebay, (look at sales topic), and kept the other one, (thanks to Steve Osbourne for the trailers in the first place!) ...

but it does make me curious, who would have put out these trailers?
Why would they have been put out?

To advertise upcoming inflight movies?
To advertise movies coming to you're local theater back in the 70's?

These are certainly, (judging by the optical film stock) from the very time of the original release of these features.

comments, ladies and gentlemen?

[Brian Fretwell]

I would go with advertising upcoming in-flight movies. After all Derann did sell some individual optical adverts, which I assume came with some of the ex-airline features.