The retirement of the legendary SR-71 Blackbird was not simply due to the end of the Cold War, but a result of its high operational costs, fierce interservice rivalry, and operational inflexibility.

The SR-72 “Darkstar,” the hypersonic successor to the SR-71 Blackbird, is being envisioned not just as a spy plane but also as a bomber, a role its famous predecessor never fulfilled. -While the SR-71 ...