Twenty-one years after the first F-35 contract was awarded to Lockheed Martin, only about half of the stealthy planes in the US fleet can fly. The largest global defense contractors, however, are poised to rake in another $16 billion in revenue for “modernizing” the plane.

Representative Nikki Tsongas (D-MA), the highest-ranking member of the House Armed Services Committee's Tactical Air and Land Forces Subcommittee, stated Wednesday that the modernization program cost was "an astonishingly high amount," which, "as far as I'm aware, greatly exceeds any cost figures previously provided to Congress."

Some US taxpayers might wonder how putting a US astronaut on the moon could accelerate from dream to reality in fewer than 10 years, yet the Pentagon, Lockheed Martin and the F-35's many subcontractors are 21 years into a single fighter jet program that still suffers from occasional surface corrosion, engine fires, oxygenation system malfunctioning and janky ejection seats.

The controversial F-35 Lightning II program is already over budget and years behind schedule. The supply chain to simply send parts to bases for fixing the planes is six years behind schedule, as the Government Accountability Office has reported.

The Pentagon's F-35 program director believes software "modernization" R&D will cost at least $10 billion over the next seven years. The US share of the development costs is 70 percent, or about $7 billion.

Speaking with Defense News on Wednesday, F-35 program chief Mat Winter explained, "It's predominantly software" that needs iterative upgrades. "I realize that this is not traditional," Winter said. Indeed, the F-35 program is the most expensive weapons program in United States history.

Throw in the costs to procure the software — after paying the contractors to develop it — and the "modernization" effort leaves taxpayers footing a cool $16 billion tab. Winter offered a glimmer of hope that the "estimate will most like come down, most likely… but I don't guarantee anything."

Not all lawmakers are buying what Winter is selling. Ohio Republican Mike Turner worried that the DoD modernization cost estimate provided in the form of a written report was so lacking in real insight that it "reduces our overall confidence the Department of Defense actually knows the answer to the question," Defense News notes.

Modernization is intended to shore up some of the plane's software bugs and glitches, providing about 53 new capabilities, the news outlet said. According to a January audit by Defense Department Director of Testing & Evaluation, the F-35's software platforms have around 1,000 existing "unresolved deficiencies."

This program seems to exhibit what some analysts call failing up: the program faces setback after setback and US lawmakers keep authorizing more and more payments for solutions to a virtually infinite list of problems. The more it fails, the more the program's budget creeps larger and larger.