Boeing was supposed to deliver a replacement for Air Force One last year, but significant delays have cost the plane maker billions on the project. They have also drawn ire from the president, who told reporters aboard Air Force One in February that he was “not happy with Boeing” and may purchase a plane elsewhere.

Boeing has not officially confirmed any changes to the $3.9 billion fixed-price contract it signed during Trump’s first term. It has absorbed more than $2.5 billion in losses on the project.

The two planes currently used as Air Force One have been flying for nearly four decades, and Trump is eager to replace them. During his first term, he displayed a model of a new jumbo jet in the Oval Office, complete with a revised paint scheme that echoed the red, white and dark blue design of his personal plane.