The Lockheed SR-71 Blackbird was a marvel of Cold War engineering, and to the perplexity and dismay of many, it was retired in 1989 (temporarily) and 1998 (permanently) without a direct replacement.

Of all the jets produced by the United States, few are as well known and beloved as the SR-71 Blackbird, first developed by Lockheed Corporation's Skunk Works in the 1960s. The SR-71 is best known for ...