Don't be fooled by that 6.
I can tell you put a lot of effort into this. I know flash is hard at first (it'll only get harder). The planes were very well drawn, I don't know how you might have done them but well done. The markings on the sides of the planes do change from plane to plane, so you might want to change them for episode 2 rather than just copying them. It didn't make a big deal but considering you put so much effort in already I wouldn't have thought it'd be that hard.
You have the same problem as I did with my first flashes, it goes very slow. You end up watching a plane fly by for about 10 seconds, which is far too long. To improve the quality of the flash, especially one like this, it's good to make the action more fast-paced and intense to give you the feeling that the planes are going really quick (as they obviously would have been). Would also be nice to see a human element to the movie other than the officers around the radar table, maybe a pilot or two so we actually know who's gonna be getting shot at, that would increase the depth of the story a bit.
The only graphically disappointing bit was the fire on the radar station at the end, it looked totally wrong. I find fire is better drawn by doing each frame seperately rather than trying to tween a single graphic, because it ends up looking like a blob moving around pointlessly.
Another thing is sound, I realise sounds for this kind of stuff is hard to come across. I find a good resource for sounds are games, do you have any flying games? If you go into the Local Disk (C: Drive) and go into program files, you can usually access sound effects from your own computer games. You can also download sound effects from websites like flashkit.
Anyway, I hope that I've given you a few things to work with anyway. The main thing that needs sorting is definately the speed of it... Speed it up, viewers don't need to stare at a plane ambling past slowly for any great length of time!
Good luck, anyway. I look forward to Part Two. Let's hope that Britain will crush the Nazi horde. :oD
6/10