Thanks for the cockpit hint Gerhard.
I'm doing just the same: Capture the video with Fraps (apparently 6 times, one run for each perspective) and put everything together in Vegas Pro.
I'm not satisfied with the youtube quality either.
You can see the difference between uploaded source material and the youtube results here, click for fullscreen images.
Source mp4 h264 encoded according to youtube recommendations found here:
http://support.google.com/youtube/answer/1722171?hl=enusing "High quality uploads for creators with enterprise quality internet connections" 1080p settings:
And this is what it looks like on youtube, pay attention to the upper left and right frames, e.g. the balloon, prop blades, wing leading edges etc.:
There seems to be no way to avoid the massive quality loss. I don't remember to have seen such bad quality a year ago. Looks like youtube puts "masses" over "quality", it's disgusting.
Best regards - Mike