I kinda think he meant a person, not a vehicle. Having tried (and failed) to put out more than one vehicle fire, I can not even imagine trying to put one out with a blanket. I have worked in places where they had boxes mounted over doors, with an easy opening latch on it. If on fire, you went to the door, hit the latch, the blanket (wool of course) dropped on you, and you wrapped yourself in it to smother the fire. Or so the plans said...

i'm not going to read thru all the other replys but i have
and i would suggest you get a decent wool blanket..try Ebay.
armys around the world used them because damp wool will keep
you warm and your body heat will dry them out..army blankets
are made a bit to "hard" a soft blanket is better..make sure
you get a big one..in the surplus catalogs i have seen some
that were just short of six feet..you want something that
will cover from top of head to toes..

Just got a catalog from Major Surplus N Survival. They had several types of blankets. IIRC, the German blankets looked good and were a large size. Cheaper Than Dirt and Sportsman's Guide usually have blankets also.
I've had done well finding blankets at Thrift stores.

Dave