We have definitely gotten a lot more interest, Chris Chadwick, president of Boeing Military Aircraft, told reporters.
Chadwick said customers in Asia-Pacific have expressed interest in the F/A-18E/F Super Hornet, a jet that can carry air-to-air missiles and air-to-surface weapons. He also said potential customers in the Middle East were looking at different versions of that fighter aircraft.
Aerospace analysts have said Boeing's Super Hornet could benefit from problems and delays with the F-35.
The multinational F-35 family of fighters is the Pentagon's costliest arms purchase, most recently projected to total more than $380 billion over the coming two decades.
U.S. lawmakers earlier in May urged the Pentagon to think of alternatives to the F-35 program if costs cannot be brought down.
Shares of Boeing were up 0.8 percent to $77.59 in afternoon trading on Tuesday.
(Reporting by Karen Jacobs; Editing by Tim Dobbyn)