We carry two small fire extinguishers in our helicopter. I brief my crew that they have two uses:
- If someone is on fire, use it on them.
- If I am trapped in the cockpit, use it to knock me out.
If the machine is on fire, move away to a safe distance and let it burn. If your car is on fire, chances are it will be totaled anyway. Why risk serious injury? Burns really suck. A built in system sounds like a great idea though if you are concerned about the car.