Ehh most people are saying the wheel model sucks and jumps around or the plane keeps looping. Well I have some solutions for you but you might already know this (in fear of getting flamed).
Wheel density on the cars are important lol duh(Gmod cars)... Well yeah for fast cars I use 1/3 the weight of what it is attached to, if your using suspension you may have to do hours of tweaking the elastics and weight.
You may find your vehicles veering to the side, this can be fixed by using more thrusters to counter this err veering or... Use the fin tool it is available for use in the RND Wirebuild server. Set the settings to "no lift" "flat surface" then depending on the fin/s weight change the efficiency to suit your vehicle.
Please give feedback, I would really like help or to help someone :|
General Mingebagger requested the plane section to be removed, I did that right away.