The U.S. Air Force's secret program to develop as many as 100 next-generation bombers that can stealthily strike any target in the world has some experts calling the $550 million per plane price tag laughable.

"I would go to Las Vegas and bet on cost overruns for this system," Hans Kristensen of the Federation of American Scientists told The Washington Post.

Another critic compared the initiative to the costly B-2 program, which was eventually slashed, and said the cost estimate is "as close to meaningless numbers can be."

The Post reported that the Air Force intends on the plane taking its first stealth flight in the mid-2020s.

In January, then-Defense Secretary Chuck Hagel endorsed the plan, arguing that it would help deter nuclear war and preserve the U.S.' global pre-eminence.

"I think the long-range strike bomber is absolutely essential to keep our deterrent edge as we go into the next 25 years," Hagel told reporters after addressing a group of several hundred airmen at this B-2 stealth bomber base in western Missouri.

The Pentagon says it also needs to modernize the two other elements of the strategic nuclear force: the Navy's fleet of Ohio-class strategic submarines and the Air Force's Minuteman 3 land-based nuclear missiles. The combined cost would exceed $300 billion, by current estimates.

Hagel noted that the 20 planes in the B-2 fleet — all based at Whiteman — are operating on 25-year-old technology. The other nuclear-capable plane in the bomber fleet, the venerable B-52, is even older.

The Associated Press contributed to this report