John Travolta's Classic Mercedes-Benz Gets JACKED

John Travolta's vintage sports car was stolen right out from under his nose yesterday in Santa Monica ... TMZ has learned.

Law enforcement sources tell us Travolta had parked his 1970 Mercedes-Benz 280SL on the street -- just a couple blocks from a Jaguar dealer.

We're told John was only in the dealership for about 10 minutes -- and when he returned ... his whip had vanished.

John went back to the Jag dealer and waited for police to show up to take a report. We're told there are no witnesses. Travolta's rep hasn't gotten back to us yet.

By the way ... that Benz can sell for as much as $100,000.