Rather than maintain two separate projects with an incredibly similar code base, the Planez functionality will be added to the Carz plugin using a configuration option. Example of implementation:
"Planez.Enabled" defaulted to false.
Once enabled, will add an extra question during the createtype conversation of "Is this a Plane?"; This will become an attribute of the Car.
If this attribute is true while driving, the flight ability is enabled and will kick in when the vehicle has reached its maximum speed (so you can't take off straight away).

Things to consider:

• Need to include the check to disable fall damage while in a plane
• Gradually decrease the speed as the player looks higher up, and accelerates while looking down. The speed modifiers could be used to achieve this.
• Possibly have a Drivable interface which has it's own method of how to move the Vehicle (Car & Plane)
• Config needs a rewrite to cater for each vehicle type to have different attributes (fuel etc.)
• Maybe we split this down the middle and have a "/carz createcar" and "/carz createplane" so it makes more sense.
• Avoid the word "Car" and make it generic "Vehicle" or "Carz Vehicle".