From: Denver Colorado
I believe they begin damaged having to do with Yugoslavia/Greece campaigns (maybe Crete, even?)
You would be better served by not flying them on Turns 1-3 rather than sending them to reserve. In a campaign game, I would put them into reserve, but not Road to ... because they are short.
I don't have an answer why it would be that you cannot deploy an air group OUT of reserve. You should get an answer during the week, I expect.
As to supply pre-requisites:
Bombers can provide "supply" but not "fuel". If you are not using SHIFT-click to perform air supply missions, you should give it a try. It provides much more control for the player. When using SHIFT-click, a pop-up screen shows what aircraft are available. However, in the bottom right of that screen is a clickable Fuel/Supply toggle. It usually begins in Fuel setting, so you won't even see Bombers that can fly Supply. Click it to Supply and you will see which bombers are available for supply missions. Finally, Bombers can only perform supply missions when they have 0 percent miles flown (i.e., first mission of the turn.
ALL aircraft wishing to perform supply missions must be within 5 hexes from a supplied rail-network hex, as well as 20 movement points or less from said rail-network hex (the latter isn't as big a restriction as the former.)
Performing Transport missions of Supply to your lead infantry corps HQs can be very helpful between turns 3 and 6 when there aren't many targets to be bombed and combats to support due to range and how far the Germans advance. Especially if you organize a corps each in 16 and 18 Armies to be 'hammers' and then fly supply to them, it can make a big difference in taking Leningrad.
Hope this helps.
Spring 2018-Playing: Demyansk Shield: Frozen Fortress; Advanced Squad Leader,
Rulebooks: ASL (always ASL), Holland'44, Demyansk Shield: Frozen Fortress