Production of the Lockheed Martin F-16 will begin to shut down or experience "significant gaps", unless the company secures new orders for the fighter by the end of the year.
Chief executive Bob Stevens said Lockheed is still waiting on procurement decisions from Iraq and Oman and from the US government, on whether to sell new F-16s to Taiwan.
Although Lockheed has told customers it plans to stop production by the end of 2013, securing additional commitments is vital to the programme, he said.
"We have, at the same time, advised that if we don't receive firm commitments for additional F-16s on or about the end of this year, then the line will certainly begin to shut down, if not have a significant gap.
"I think that's caused a number of our global customers to evaluate their inventory needs," he added.
The company expects to deliver about 40 of the aircraft next year, with a large proportion of them assembled by Turkish Aerospace Industries for the Turkish air force, under a 2007 deal for 30 F-16 Block 50+ fighters.