Answer: tailfins

AnswerCrossword Clue
TAILFINSFlashy '40s-'60s Cadillac features
TAILFINSProminent feature of the Batmobile
TAILFINSDetroit-made adornments.
TAILFINSThey were big in the '50s
tailfinsTAILFIN, a fin at the posterior end of a fish