[Sithis]

You can simply set the vehicle health to a value higher than 1000 (https://sampwiki.blast.hk/wiki/SetVehicleHealth) to make it practically invincible. Make sure to reset it from time to time, to make sure it doesn't explode whenever the vehicle has received enough damage.

You can add nitro to a vehicle using https://sampwiki.blast.hk/wiki/AddVehicleComponent.

The components you want to add are as follows:

1008 nto_b_l Nitro 5 times
Most cars, Most planes and Most Helicopters

1009 nto_b_s Nitro 2 times
Most cars, Most planes and Most Helicopters

1010 nto_b_tw Nitro 10 times
Most cars, Most planes and Most Helicopters