My 1988 buick lesabre has the felt ceiling material fallen away from the roof - how do I get the felt material stuck back up to the ceiling?

Just rip the whole thing out, if you haven't already. Your good visibility for driving safely should come first. The only viable solution is to have it professionally redone, which should cost about $150.

Any parts store has replacment head liner just remove mouldings and visors disconnect dome light and remove old headliner. be sure to clean old one by rubbing lightly with a brush after pulling the old cloth away all thats left is a small bitn of foam wich rubbs away. now u spay glue the shell and turn the headliner over and spay that to with a good even coat and apply from center out so u get no wrinkles fold edges 1 inch and cut and glue then cut out your holes gently and replace head liner simple as that.

It's pretty hopeless to get it stuck back up right. It has a sponge backing that tears off when you glue it. The only right way is to get a new ceiling liner and put it up. But I assume your car is too old to want to do that.

I have tried spray on adhesive. I took the liner off from the dome light to provide a hole for me to poke my arm up through and spray the adhesive. But hot sunlight made the glue come loose.

The only partially effective remedy I found was to take off the doorway trim and tape the edges of the liner up tight and hold that in place with the doorway trim. It still sagged, but I could see out the rearview mirror.

I tried a hot iron to melt the glue and stick it up. It worked for about ten minutes.

You might try stiff strips of thin wood on the outside of the liner, wedged against the doorway trim and pressing up against the liner.

You might try some quite thick glue, so that it would soak through the sponge backing and penetrate the fabric. That would show spots on the ceiling, but it might hold it in place.

Good luck!