I haven't played this game in a very long time. Shame on me.
Some tips I can add that others haven't:
I never used to loop, but I do remember doing lots of horizontal 360s to get behind enemies and to search for enemies.
When strafing, stay at the bottom of the screen, but fly high. That way, you can shoot things that are far off. I also think you are alittle harder to hit when you are high.
If you are going down in flames, try and take out another plane or balloon with you. You will die but it's fun.
If you are going down, and your pilot isn't dead, you can always try and land. It's an iffy affair - you have to fly parallel to the ground, edging down slowly, and gently touch with the earth.
The levels containing 5 allied planes versus 20 Luftwaffe are some of the most chaotic battles I have ever had the pleasure of participating in on any game, period. You'll love it when you reach them.