Lockheed Martin stocks were down about four percent in early trading Monday after President-elect Donald Trump blasted "out of control" costs for the F-35 stealth fighter program.
With a current development and acquisition price tag of $379 billion for a total of 2,443 F-35 aircraft -- most of them destined for the Air Force -- the Lockheed Martin-built plane is the most expensive in history.
"The F-35 program and cost is out of control. Billions of dollars can and will be saved on military (and other) purchases after January 20th," Trump said on Twitter, as Defense Secretary Ashton Carter was in Israel to celebrate delivery of the country's first two of the Lockheed Martin fighters.
Once servicing and maintenance costs for the F-35 are factored in over the aircraft's lifespan through 2070, overall program costs are expected to soar to $1.5 trillion.
The US Air Force declared an initial squadron of F-35A fighters "battle ready," in August, after reports of cost overruns and delays.
The Air Force's F-35A is one of three variants of the aircraft, designed to conduct conventional landings and take-offs.
The F-35B, used by the Marine Corps, is capable of short take-offs and vertical landings, and the Navy's F-35C is built for use on aircraft carriers.
Trump has frequently turned to Twitter to vent his outrage about anything from critiques of Saturday Night Live, a weekly comedy-variety television show, to attacking Boeing for the cost of designing a new version of Air Force One, the presidential plane.
Proponents tout the F-35's radar-dodging stealth technology, supersonic speeds, close air-support capabilities, airborne agility and a massive array of sensors giving pilots unparalleled access to information.
But the program has faced numerous setbacks, including a mysterious engine fire in 2014 that led commanders to ground planes until the problem could be resolved.
Other issues have led to delays and cost overruns, including software bugs, technical glitches and even a faulty eject system that risked killing pilots who weighed less than 136 pounds (62 kilos).