Lasse,
When questions are never answered...however, it takes less time to design these planes with the format they are using than it does in some of the other sims that use painted 2d cockpits. Since the cockpit we see is designed at the same time the airframe is, time between planes will be greatly reduced.
Remember also, that there are going to be trains to blow up, tanks to mess around with and other objects and the strat system isn't complete yet. We do need more than planes for a good game but like you I wait with bated breath for the next ones to come out.
See this as an opportunity to get real familiar with a few at a time. You may not wish to fly all of them and may have a favorite plane but it will give you good insight into the strengths and weaknesses of your opponents when they choose one of the others.
MarkAT