Boeing’s chief executive said the company should never have taken on the unique set of risks it negotiated.

“You know, Air Force One, I’m just going to call a very unique moment, a very unique negotiation, a very unique set of risks that Boeing probably shouldn’t have taken,” Boeing CEO David Calhoun said on Wednesday, “But we are where we are, and we’re going to deliver great airplanes, and we’re going to recognize the costs associated with it.”

Starting at a price of $5.3 billion, then-President Donald Trump negotiated it down to $3.9 billion. The agreement was in places for two new aircraft that would be in use by 2024.

A Trump spokesperson has not yet responded to a request for comment.