Ah, forgive my ignorance Nashwan. I was under the impression that the Spit9 we had was a 1943 plane, but I wasn't sure, so i asked. But, if we went from a Rolling Plane Set, the war lasted from 1939 until 1945. 1943 is towards the middle, but after the exact middle. That is what I meant when I said "people could not fly the Spit9". I know the La7 and Niki are 1944 planes- so I guess they STILL couldn't fly those for half the month.
So, in a 6 year war, the difference between a 1943 plane, and a 1944 plane isn't all that great, IMO. You'd be able to fly the Spit a few days before La7 and Niki, but you wouldn't be able to fly it for around half the month. I guess you could fly the SpitV instead, I don't know the difference anyway.