- For the tail fin of an aircraft, see Vertical stabilizer.
The tailfin era of Automobile styling encompassed the 1950s and 1960, peaking between 1958 and 1960. It was a style that spread worldwide, as car designers picked up styling trends from the American automobile industry.
General Motors design chief Harley Earl is generally credited for the automobile tailfin, introducing small fins on the 1948 Cadillac (automobile). Harley credited the look of World War II Fighter aircraft for his inspiration, particularly the twin-tailed P-38 Lightning. As jet-powered aircraft, rockets, and space flight entered into public recognition, the automotive tailfin assemblies (including tail lights) were designed to resemble more and more the tailfin and engine sections of contemporary jet fighters and space rockets.
Some sub-models of the 1937 Cadillac Fleetwood, which predates the P-38, also contained hints of tailfins via projecting tail-light "paddles", although it is unclear if this influenced later fin designs.  The 1941 Cadillac Series 63 4-Door Sedan also had a form of jutting tail-lights, although milder than the 1937 Fleetwood. Even though the 1948 model was the first conscious effort at fins, the earlier partial occurrences may have made the concept more acceptable to consumers and designers. (The war produced a gap of Cadillac model production between the early 40s and late 40s as factories turned to military goods production, interrupting the development of the fin concept.) The Cadillac 1948 fin styling proved popular and its use spread to other models in the General Motors family of brands. Soon it was adopted by other manufacturers; Chrysler's Virgil Exner in particular took the tailfin idea on board. As confidence grew in the styling trend, the fins grew larger and bolder.
The most extreme tailfins appeared in the late 1950s. Many consider the fins on the 1959 Cadillac Eldorado to be the largest and most outrageous ever fitted. (However the German-made Amphicar had slightly higher tailfins.) Those fins were too much for many customers, however, and the tailfins shrank after that point. Within a couple of years, tailfins had become much less prominent, and by the mid 1960s, they were gone on many models. Vestigial tailfins remained on American cars into the 1980s, with the sides of the quarter panels often being raised above the trunk lid and the corner sharp-edged, or at least raised. Cadillac was one of the last makers to phase raised edges out, with vertically-arranged tail-light assemblies as well, on all of their products (except the Allante) all the way to the early 1990's.
Mercedes used something similar to fintails (nicknamed "heckflosse" in German), but they claimed that these were not fintails but "sight lines" to make it easier to determine the corners of the vehicle.
Examples of Tailfin Styling:
- Buick LeSabre, 1959-1960
- Cadillac Eldorado, 1948-1966
- Chevrolet Bel Air, 1957
- Chrysler Imperial, 1955-1963
- Chrysler New Yorker, 1956-1961
- DeSoto Fireflite, 1956-1960
- Dodge Lancer, 1955-1959
- Fiat 2100, 1959-1961
- Lincoln Capri, 1955-1957
- Moskvitch 408 - Moskvitch 412
- Peugeot 404, 1960 - 1975
- Plymouth Fury, 1956-1960
- Vauxhall Cresta PA, 1957 - 1962