The car in the Supernatural universe is almost a character itself. While the showrunner Eric Kripke initially considered a 1965 Mustang for Sam and Dean, he ultimately settled on an iconic 1967 Chevy Impala, nicknamed "Baby." The car is a recurring feature throughout the 15-season run of the hit show and is integral to the Winchester brothers' mission.
Throughout the series, Dean uses Baby as his primary mode of transportation. He drives it during his vision of a young John and even slams the back door on a possessed Deputy Donelly. The Impala is also a key weapon in the fight against supernatural creatures. The resurrected Mary Winchester is seen admiring the vehicle in Keep Calm and Carry On, presumably reminiscing over times she spent with her husband in the backseat.
Occasionally, the Impala is not available and the Winchesters have to rely on other cars. This was the case in season 5's Swan Song when Dean's Impala is not at his gravesite upon returning from Purgatory. Dean hot wires a Mercury Monterey in the episode and the brothers use the car for their hunts until they can get Baby back. During season seven, Dean occasionally steals classic American Muscle cars from Bobby's Salvage Yard and uses them as a means of transport. Jensen Ackles has discussed this tendency to steal cars in interviews and during conventions. In fact, he once said that the main reason he loves the show is because of all the cool cars he gets to drive.