Absolutely agree. This should be our landing place, a somewhat unique environment that identifies our character and our achievements. But most of all it should encourage us. It should make us want to load up the game, to interact, and to take the plane out. 2020 kind of had this, but it was a super large hangar, which did not inspire me - it’s not meant for the kind of aircraft and flying I’d call home.
My suggestion is to have several base types of hangars that “scale” with certain types of aircraft. Possibilites could range from a simple t-hangar, a more modern hangar, or a large corporate/airline style hangar. Dimensional limitations for each type should be clearly specified and we can assign aircraft to one of multiple hangars as long as they fit (otherwise they go out on the ramp, which is another option, probably should be the default). All sorts of customizable accouterments should be available.
Which airplane to be displayed should be selectable, setting either by default, or “last flown” from that hangar, or perhaps pre-selected from a list (to add immersion as you arrive). Perhaps multiple aircraft can be displayed if dimensions and number of spots allow.
The hardest part is the transition from inside to outside - where would this hangar be located? Or is it possible to have a generic transition that allows it to look as if it is anywhere?
Alongside all of this - they need to come up with better procedurally-generated airport building objects, especially for smaller airports. Many generated buildings default to being about 2-3x the height of their real-world counterparts, which looks silly. Most don’t have realistic-looking doors (facing the wrong way, or not being present at all). It’d be jarring to pull up to a 36’ tall t-hangar at the end of your flight, then be “transported” into your appropriately-sized 12’ tall one.