A legend of sorts deals with the origin of the 1948 Cadillac tailfins; here is one version, and I have read other accounts over the years. The story goes that GM styling chief Harley Earl learned of the then-futuristic Lockheed P-38 Lightning fighter and took some members of his styling staff to see an example. Most accounts mention that the P-38 was top-secret at the time. That last item is not true, which is the point of this post.
Edson Armi's book on automobile design (Amazon link here) has the following account on page 76 of the hardcopy edition:
Furthermore, images of the P-38 had been publicly seen for at least two years previously, so the plane's appearance would have been known to Earl and the stylists before they made their Selfridge Field visit. That visit probably served to create a greater visual impact for team members than photos would have yielded.
Cross-posted at the Car Style Critic blog.