The rare car was stolen on Sunday in the area, while Travolta was visiting a Jaguar dealership.
Police launched a "grand theft auto investigation" into the matter, but no eyewitnesses have yet been found.
Sgt Richard Lewis of the Santa Monica Police Department said that the theft probably took place within a "ten-minute window" and said it's unclear if Travolta was specifically targeted by the thief.
Police have now offered to pay $1,000 (£649) to anyone who can help them identify the person or persons who took Travolta's vehicle.
Travolta's vintage 1970 Mercedes-Benz 280SL is extremely rare, with 2,400 left in circulation.
The missing Mercedes-Benz 280SL is said to be worth anywhere between $35,000 (£22,267) and $100,000 (£63,621).
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Watch John Travolta in a clip from From Paris with Love below: