WEBF,
My guess concerning the hangar relates to the space available on the ship. The space available for a hangar on Albion would probably only be able to hold between 2 to 4 helicopters of medium ie. Seaking/Merlin size. In order for a beach assault to be at its most effective, the troops need to be moved ashore rapidly and in numbers, not easily achieved with such limited air assets.
It looks as if the designers/procurement have opted for a larger flight deck instead. As the ship is not designed to operate alone, the larger fligth deck would allow air assets from carriers/HMS Ocean to operate more efficiently and so 12 to 15 helicopters could easly form an aerial conveyor to rapidly move large quantities of troops or vehicles ashore. The larger flight deck also allows for more efficient vert. rep. and load lifting, again, meaning a faster operation. The most dangerous element of any beach landing is as the fully loaded LPDs near the beach and start to unload. Time spent in this dangerous area is thus minimised.
IMHO this idea of groups of warships is also the reason why Albion has no missile system. It does have a last ditch point defense system with goalkeeper which in fairness could have saved a lot of lives if we had it in the Falklands. It is not defenseless, but its primary role is not fleet air defense so it is reliant upon other ships for protection.
Just my thoughts,
Obs cop