The Doctor sits in a 1957 Chevrolet Bel Air
The Bel Air was a mid-20th century automobile built on Earth and sold under the brand of Chevrolet.
A holographic representation of a 1957 Bel Air was used in a holodeck program created by Tom Paris for The Doctor's date with Denara Pel. The two spent an evening in the Bel Air atop the hills overlooking Utopia Planitia on Mars – Paris' idea of a perfect date. (VOY: "Lifesigns")