Glider factory might be the term many people would use. Or more generally, aircraft factory. Most are built and kept in a HANGAR. It's the big building where they are repaired and stored.
I have taken up flying as a hobby - and the microlight I fly is repaired and kept in the hangar.
Also, when I was very young, I worked at an airfield where they built the vertical take-off military jets - and they were built in a hangar.
HANGAR is the building (like a very large shed!)
Aircraft factory is the more general term.