Ford also decided that the market for two-passenger cars was too small to justify competing with Corvette and foreign sports/sporty cars. Rather than dropping the model -- one possibility -- it was decided to create a compact four-passenger Thunderbird for 1958. The risk was that fans of the two-passenger Thunderbirds would be alienated by the change. As it turned out, the new Thunderbird considerably out-sold the first version, as the link above states.
As for 1958 Thunderbird styling, it appeared at the height of the tail fin fad. Also, Ford advanced styling studios during the early 1950s seemed to favor jet fighter or science-fiction space ship styling themes. So did those of other makers, but I have the impression that Ford did more of this kind of thing than its competitors. The result was that this practice influenced the design of the 1958 Thunderbird.
Ford Muroc from the early 1950s, named after the experimental flight test center in California.
A similar vintage half-model (the mirror behind it creates the image of a complete car).
Note the airplane propellor motif at the front and the aircraft-type exhaust pipes in the wheel opening. The theme here is derived from World War 2 fighter planes rather than jets.
The Ford Atmos non-functional concept vehicle of 1954. Clearly influenced by jet fighters such as the F-86 Sabre. Such was Ford's advanced styling a couple of years before the 1958 Thunderbird project was launched (probably no later than 1956, more likely 1955).
A 1957 Thunderbird, Mecum auctions photo. This was the final model year of the original design. Its facelift included a new grille and the low, canted fins. I always considered this the best Thunderbird design of all.
A "for sale" image of a 1958 Thunderbird. Retained are the roof with blanked quarter panels (or wide C-pillars, depending on how one thinks of these things), along with modestly canted tail fins. The nearly-oval grille and hood air scoop décor were also carried over. The sculpting on the lower side is suggestive of aeronautical/spaceship concepts.
A North American F-100 Super Sabre, a supersonic fighter revealed in 1954. Note its air intake.
One might argue that Thunderbird grilles for 1957 and 1958 were inspired by the F-100.
Side view, via Mecum. The decorations on the lower sculpting are suggestive of air outlets, particularly those used for boundary-layer air control on jet fighters with side intakes.
Barrett-Jackson photo of a 1957 Thunderbird. Round tail lights were a Ford image marker in those days, having first appeared on 1952 models. Combined with the tail fins and the tail pipe exhausts immediately below, we find a definite jet-fighter feeling here.
1958 Thunderbirds stepped up this theme by adding a second set of round tail lights and housing them in what might be considered jet exhaust outlets. A result was the rather cramped central zone where the license plate is housed.
View of the rear used for publicity. The theme is certainly jet-fighter inspired with space ship overtones. I consider the faux-outlets too large, and one tail light each as sufficient. I suspect the use of quad tail lights was due to the presence of those awful quad headlights up front.




















































