This mod makes the old civilian bus have wings and can fly reasonably well. It is very fun to mess around with. There is a normal and ludicrous mode. Ludicrous basically makes it harder to take off but fast as lightning. Ludicrous can also not gain altitude, and trust me, that's a good thing. Ludicrous is also very glitchy.
There's an awesome tutorial made by Protato on how to install mods, you can visit it by clicking this link:
1.0.1 Fixed the mod not working because of me being stupid
1.0.0 Initial Release