Multi track steel hangar doors that may cross each other. If height is limited then the hangar can be made shorter by using a tailgate.
Pros and Cons
Do not use tailgates unless you have to. Doors crossing the tailgate gap are tricky (but we can do it if vital). It is better to make the whole doorway full height, or use outriggers. Don't use for high tail plane aircraft, or on a hangar that requires full opening.