The fleet of 33 U-2s was supposed to be replaced with RQ-4 Global Hawks, high-tech drones used by the Air Force since 2001.
But the U.S. Defense Department this week proposed delaying the retirement of the U-2s as a result of Pentagon spending cutbacks, the Los Angeles Times reported.
The Global Hawk, with a price tag of $176 million apiece, had "priced itself out of the niche, in terms of taking pictures in the air," Deputy Defense Secretary Ashton Carter said at a news conference Thursday. "That's a disappointment for us, but that's the fate of things that become too expensive in a resource-constrained environment."
The Pentagon won't say how much it'll cost to operate the U-2s for security reasons, the Times said.
The U-2, used since 1955, is probably best known for being shot down over the Soviet Union in 1960 and the capture of pilot Francis Gary Powers. But it still serves a key national security role, hunting al-Qaida forces in the Middle East, the Times noted.
"It's incredible to think that these planes are flying," said Francis Gary Powers Jr., Powers' son and the founder of the Cold War Museum in Warrenton, Va. "You'd think another spy plane or satellite or drone would come along by now to replace it."