On his social media platform, X, he reposted a video of synchronized drone swarms flying in elaborate formations and added, “Meanwhile, some idiots are still building manned fighter jets like the F-35.”

And below a comment from a user who said, “Drones are the new level of warfare,” Musk replied with the “100” emoji, which indicates strong support.

Meanwhile, some idiots are still building manned fighter jets like the F-35 🗑️ 🫠
pic.twitter.com/4JX27qcxz1

— Elon Musk (@elonmusk) November 24, 2024

In subsequent posts on Sunday, Musk said the F-35 has a “s–t design,” claimed drones are more efficient than manned jets at delivering munitions, and downplayed the effectiveness of stealth technology.

The Defense Department stood by the F-35 and noted its broad reach.

“We have combat-capable aircraft in operation today, and they perform exceptionally well against the threat for which they were designed. Pilots continually emphasize that this is the fighter they want to take to war if called upon,” a spokesman for the Pentagon’s F-35 joint program office said. “The air system’s international footprint amplifies the platform’s benefits, and it is the aircraft of choice for partners and allies. The program includes the U.S. services, seven international partners, and 12 foreign military sales customers, and FMS interest in the platform continues to grow. In the next 10 years, there will be 700 F-35s in Europe, and only 60 of these will belong to the U.S.”

Lockheed Martin, which is the prime contractor, said the company will work with the new administration and backed the F-35’s capabilities.

“As we did in his first term, we look forward to a strong working relationship with President Trump, his team, and also with the new Congress to strengthen our national defense,” a company spokesperson said in a statement. “The F-35 is the most advanced, survivable, and connected fighter aircraft in the world, a vital deterrent and the cornerstone of joint all-domain operations.”

Lockheed shares closed down 3.75% on Monday, and Northrop Grumman, a top F-35 subcontractor, retreated 2.3%. RTX, whose Pratt & Whitney unit makes the jet’s engines, dipped 1.8%.

Musk’s critique sparked vigorous debate online about the F-35. On Monday, he doubled down with another post, alluding to its conception as a multi-role fighter that serves different branches of the military.

“The F-35 design was broken at the requirements level, because it was required to be too many things to too many people,” he wrote. “This made it an expensive and complex jack-of-all-trades, master of none. Success was never in the set of possible outcomes. And manned fighter jets are obsolete in the age of drones anyway. Will just get pilots killed.”

To be sure, the Pentagon has been flying a range of drones for decades, including for surveillance missions and air strikes. And a concept for a future next-generation air dominance program includes a mix of manned and unmanned fighters.

But Silicon Valley defense startups like Anduril are also developing drones while looking to change how the Pentagon develops and buys weapons. In fact, Anduril’s executive chairman has reportedly consulted with Trump and his team about revamping the military and is even in the running to be deputy defense secretary.

Meanwhile, hundreds of F-35s are already in use in the U.S. military and among top allies around the world. Over its production cycle, the Pentagon plans to buy about 2,400 F-35s for the Air Force, Navy, and Marine Corps, to replace aging, non-stealth fighters.

The Pentagon first awarded Lockheed the contract in 2001, but the program has been a perennial punching bag owing to cost overruns, delays, and its enormous price tag.

After including the expenses to develop, manufacture, operate, and maintain its eventual fleet of F-35s over the fighter’s total service life, which could extend into 2088, the Defense Department estimates that the F-35 will cost $1.8 trillion, making it the Pentagon’s costliest weapons program.

A recently declassified report from the Defense Department’s weapons testing chief found that the F-35’s reliability, maintainability, and availability are “below service expectations.” In response to that report, Lockheed has said the F-35 “consistently meets or exceeds the reliability performance requirements we are contracted to deliver.”

In a Wall Street Journal op-ed Wednesday laying out DOGE’s agenda, Musk and fellow cohead Vivek Ramaswamy didn’t highlight any weapons programs but noted the Pentagon recently failed a seventh consecutive audit, “suggesting that the agency’s leadership has little idea how its annual budget of more than $800 billion is spent.”

Any changes to the defense budget and weapons procurement ultimately must go through Congress, and F-35 production is spread across various districts and subcontractors.