Tired of paying to park at the airport? If you don’t mind letting a stranger drive your car while you’re gone, you could make money instead — and even get a free car wash.

That’s the idea behind FlightCar, a new car-sharing business set to start operating at Logan International Airport at the end of the month. The San Francisco-based company, started by three teenagers earlier this year, plans to rent departing airline passengers’ cars out of an East Boston parking lot. If someone rents a car, the owner gets a cut of the earnings ­— $10 per day for newer cars — as well as a free car wash and ride to the airport in a Lincoln Town Car.

If no one rents the car, well, the parking is still free.