Alright, so you're squadron has all of their planes assigned and you have no more room in your zepp hangar, but you jsut saw the coolest new plane in the showroom... What do you do?
These rules that I came up with are for just such an occasion. I have made rules regarding plaen storage. Planes may be stored on either a zeppelin or at an airfield. Planes in storage are in one general piece, but may have their wings removed, engines exposed, guns covered, be covered with a tarp or placed in a shed...etc. A plane that is in storage may not be used. However, you may take a plane out of storage. To do this, you must have either enough room for more ready planes or must put a currently ready plane in storage. This takes one mission. In otehrwords, if you're playing a campaign, and you finish mission 3, if you get a plane out of storage immediately afterwards, it wil lbe ready for use by mission 5. The pilot of the to-be-ready plane may not participate in the misison while his plane is being readied.
Now, as to how many planes can you store...
Zepplins and airfield (or even carriers for that matter) will have a certain number of planes taht they can keep ready. Any moving airfield (that is, a zeppelin or carrier) may store 1/2 as many planes as it keeps ready. So if your zepp can hold 4 planes, you can keep 2 stored. An airfield has more room, and can hold as many planes in storage as it has in readiness. So if your airfield has room for 12 planes ,you may store 12. There is no cost associated with storing or readying a plane, but every 2 missions that the plane is in storage, you must pay a maintenance fee (for cleaning of engines and guns, maintenance of controls, physical cleaning of the airframe, small part replacements, and so on) equal to 1% of hte planes purchasing cost. So a plane that cost $10,000 requires a maintenance fee of $10 every 2 missions.