Etymological Note: This is directly related to the term bomb ‘an old, dilapidated car,’ which goes back to at least the 1950s. There is also a now out-of-fashion sense of bomb ‘a hot-rod or fast car.’
Citations:
1981 Jonathan Mann Globe and Mail (Toronto, Can.) (Aug. 14) “Follow the leader Tactics change in 6-hour event” p. P49: The limited sportsman division, with cars of up to 255 cubic inches, the mini-modified division, with cars up to 2,200 cubic centimetres, and the bomber division, with six-cylinder street-stock cars, will round out the card. 1994 James Dempsey Telegram & Gazette (Worcester, Mass.) (May 4) “Hot rod is epitome of cool” p. B1: It’s not that the Old Bomber is on its last legs, you understand. Everything still works fine. Properly nurtured, this “85 Chevy could probably go another hundred thou before giving up the ghost. But the old dear wouldn’t win any beauty contests. 1996 Perri O'Shaughnessy Invasion of Privacy (July 1) p. 370: I took him out to his car and made it up to him. It was our first time. He wasn’t very good. I got out and got in my old bomber of a car and went home. 1997 Jo Ann Shroyer Secret Mesa (Oct. 10) p. 74: Mercer-Smith tore into the parking lot in a rusty yellow 1970s vintage LTD, a boatlike bomber of a car. 2002 John Case Eight Day (Nov. 26) p. 43: It didn’t seem like a good idea to arrive at Adele Slivinski’s office in the Bomber—it was a car that tend to make people skeptical of the driver. 2005 Stacy Ervin West Liberty Index (Iowa) (Apr. 5) “Racing: Kile family races together, stays together”: When Kurt was 15, his parents bought him a “bomber” car, a vehicle which resembles some street cars and is also known as hobby stock.