tetsujin28, take a look at the air combat rules from Pinnacle's Dead from Above. Some of the best air combat rules I have ever seen. Smooth, concise, fun and d20, they are a real treat. Yes, you will need to tweek things a bit but hey it's worth it.
You should be able to find Dead from above at your FLGS.
That's right. But conversion should be a simple task as most of the planes featured in Dead from Above are nimble dog-fighters not unlike those in Crimson-Skies.
The core rules for Weird Wars do not. They provided them in Dead from Above. It's a real slick system using an adventage meter ranging form 0 to 10, the higher the number the greater the advantage in air speed and position. All movement and combat cost position. The more aggressive your attack the greater the cost. That point blank shot using all your guns may have taken out the Bf-109 but now his wing man is right on your tail. They include rules for bombers and defensive gun fire. Its great fun. My friend and I would play quick matches over lunch.
For the price, about 18 bucks I think (you can probably find it cheaper on eBay), you get an excellent rule set. Get it, get it now!