My first recommendation to you is change your sounds.
"Huh?"
You probably don't realize, but the default sounds this game comes with are pretty weak. You
especially want to change the default explosion sound. It sounds like a bug hitting a screen door. Members of the community have created a far more immersive sound experience. Do a search for Mitsu's, Twinboom's, or Ranger's sounds. They are downloadable with installation instructions. I recommend mixing your favorite sounds from all.
Use Mitsu's explosion sound.
The game reads Aces High II/Sounds/Explode4.wav as the sound it plays when a plane explodes in flight. Here is Mitsu's explode4
http://www.mediafire.com/?uyi0yc2tlxeDownload that file, and replace your default explosion sound. It SHOULD be explode4.wav, but I've installed so many soundpacks that maybe my directory is slightly off. In any case, browse through your explosion sounds until you find the familiar one, and replace it with Mitsu's.
While more visual explosions would be nice, I doubt it's going to happen. This is the next best thing.