A member of the Senate Armed Services Committee charged Jan. 3 that President-elect Donald Trump’s critical tweets about the Lockheed Martin [LMT] F-35 are sowing uncertainty in the fighter jet’s industrial base, as well as among the U.S. military and allied forces.

More than 1,250 F-35 suppliers across the United States “need to plan production and hire and train new workers now,” Sen. Richard Blumenthal (D-Conn.) wrote in an op-ed in the Hartford Courant. “The mere suggestion that production should be slowed or stopped threatens to create confusion and uncertainty among the manufacturers and their supply chain.”

Citing the F-35’s cost overruns, Trump tweeted last month that he has asked Boeing [BA] “to price-out a comparable F-18 Super Hornet.” But while Blumenthal, whose state is home to F-35 engine-maker Pratt & Whitney [UTX], acknowledged that the new aircraft can and should be made more affordable, he dismissed Trump’s idea as “nonsensical.”

“The two jets, by design, are not comparable,” Blumenthal wrote. “The F-35 has stealth and strength that the older fighter cannot match — along with advanced technology that cannot be redesigned into the F-18.”

Blumenthal also pointed that three F-35 variants are under development to meet the distinct needs of three services: the Air Force, Marine Corps and Navy. By contrast, the F/A-18E/F Super Hornet, which achieved its initial operational capability in 2001, is a Navy plane.

Separately, Blumenthal, whose state is also home to submarine-builder General Dynamics [GD] Electric Boat, revealed that he discussed submarines, the F-35, cybersecurity, “Russian aggression” and other topics in a Jan. 3 meeting with retired Marine Gen. James Mattis, Trump’s nominee to be defense secretary.

“I was encouraged by [Mattis’] clear commitment to American air superiority and the important role of the F-35 program in sustaining and enhancing it,” Blumenthal said in a statement. “I was also heartened by his understanding of the strategic advantage our submarines provide to our national defense and vital security interests.”

But Blumenthal stopped short of backing the nomination. He noted that Mattis, due to his recent military service, will need a congressional waiver to lead the Pentagon.

“While General Mattis is a highly qualified nominee, preserving civilian control of our military is a bedrock principle critical to our democracy,” the senator said. “I will carefully weigh whether a statutory waiver is warranted with this nomination.”