I recommend checking out LinkTank for some guidance on converting a Weapon (used by players) to an ONSWeapon (used by vehicles). It already has the tricky bits figured out. For the most part you can attach the link tank weapon to the raptor and then switch the weapon mesh to be the raptor's instead of link tank turret.
You can download any of the mods on the server from the redirect. They are compressed and you need to use the 'ucc decompress' command to decompress them. Another way is to use the batchexport command on the omni-fullvehicleloadout map. It has almost everything in it and gives you a lot of code to borrow from.
When I initially started, I used the cache extractor tool to extract everything so I could play locally. This also gives you a lot of the .u and other files like textures, sounds, etc.
I had an idea for a link flyer also, but I abandoned it. I was remaking the Dropship vehicle to have healing powers like the Medivac from Starcraft. I have the textures done. I'm not sure why I abandoned it. I think I was afraid it wouldn't get used much.