FORT WORTH, Texas — Despite lingering questions about the U.S. Air Force’s commitment to buying 1,783 F-35 Joint Strike Fighters, Lockheed Martin’s new head of the aircraft program expects growing international demand for the stealth jet, she told reporters Thursday.

“We really haven’t seen any sort of diminishing interest,” Bridget Lauderdale told reporters during a June 10 visit to Lockheed’s F-35 production line in Fort Worth, Texas. Defense News accepted travel and accommodations from the company.

“As the jet performs — and frankly as, for example, our European partners are able to operate together and see the power and the strength of the capabilities on the platform and particularly as they are interoperating in their missions — we are seeing a stronger conviction around what this means to the security of their individual nations and to the effectiveness of the alliances,” she said. “I would say the airplane is doing its job and selling itself.”

Lauderdale pointed to ongoing fighter competitions in Canada, Switzerland and Finland. Each is expected to either choose a victor or further narrow the pool of competitors in 2021. Lockheed is confident the F-35 will be “very hard to beat,” she said.

Beyond that, other nations have shown a “great deal” of interest, though Lauderdale declined to elaborate on which countries could seek to become F-35 customers in the near future.

The company’s optimism stands in sharp contrast to a rising tide of criticism regarding the F-35′s cost relative to its capabilities. Although initially conceived as a low-cost fighter, the total cost of the F-35 program could amount to about $1.7 trillion once all development, procurement and sustainment costs are factored in.

The program has made progress in lowering unit costs for the F-35A conventional-takeoff-and-landing model to below $80 million — about the cost of a fourth-generation fighter. However, operating and sustaining the jet remains expensive, with cost-per-flying hour currently set at about $33,000 in 2012 dollars.

The U.S. Defense Department requested $12 billion for 85 F-35s in fiscal 2022. Only the Navy included additional F-35Cs on its annual unfunded priorities list.

Air Force Chief of Staff Gen. CQ Brown has said the F-35 will to be the “cornerstone” of the service’s fighter fleet. However, cost pressures may not allow the service to purchase the full program of record, which stands at 1,763 F-35As. Instead, Brown said, the Air Force may be forced to purchase a less expensive fourth-generation fighter to replace some of its F-16s.

House Armed Services Committee Chairman Rep. Adam Smith — who famously called the F-35 program a “rat hole” in March — has repeatedly expressed frustrations over the F-35 program’s costs.

“Some argue that people like me, who are willing to criticize the F-35, are simply ignorant about the classified capabilities of the program,” Smith, a Washington Democrat, wrote in a May op-ed for Defense News. “It’s a clever argument. How can it be refuted publicly? We can’t talk about these details because they’re classified.”

“[But] I know the capabilities being referenced; I have received the classified briefing on many occasions,” he said. “The F-35 has yet to actually deliver many promised capabilities.”

In April, Reps. Donald Norcross, D-N.J., and John Garamendi, D-Calif., warned they will not support increased F-35 procurement beyond the levels requested for in the FY22 budget — a pivot from previous years when lawmakers included funding to buy additional planes.

However, the program still retains widespread support throughout Congress, with more than 130 lawmakers signing a letter in May to advocate for increased investments in F-35 procurement, modernization and sustainment.

Those lawmakers have found an ally in the International Association of Machinists and Aerospace Workers. The union, which represents more than 250,000 workers who directly and indirectly manufacture the F-35, has stepped up its lobbying efforts on behalf of the program.

Speaking to reporters at Fort Worth, Hasan Solomon, the group’s political and legislative director, argued that F-35 production provides high-paying employment for skilled workers, similar to the types of jobs President Joe Biden hopes to create in his “Build Back Better” campaign.

The union will use “every political and legislative tool at its disposal” to protect the program, Solomon said.

“We’ve been applying pressure to members of Congress to make sure that this program is adequately funded,” he said. “We tell them point blank: You can’t say that you support veterans, and then you don’t support their jobs, those good jobs here at Lockheed.”

Lockheed has engaged lawmakers through its government affairs office, but Lauderdale — who became the company’s F-35 program manager in April — has not met with Smith or others who have criticized the program.

“We appreciate every opportunity we have to engage with the chairman and bring the facts and data around the performance of the airplane — the affordability of the airplane, the availability of the airplane — and have confidence in those dialogues that we’re bringing forward the best information to inform prospective decisions going forward,” she said.