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.

Questions abounded. This luxurious gift from the Qataris presented all sorts of concerns — ethical, legal, logistical, mechanical.

“I think it’s a great gesture from Qatar. I appreciate it very much,” Mr. Trump said.