EVERY naval carrier aircraft except the A-4 Scooter has folding wings.
They hold up well in naval service, and add a small amount to the
weight of the aircraft.

As far as T-hangars go, obviously you wouldn't have T-hangars in the
first place if the wings folded. A lot of airplanes don't fit well in
T-hangars anyway.

Change; it's a wonderful thing.