A little more than a month before the inauguration of President-elect Donald Trump, Iran’s national airline inked a $16.6 billion deal with The Boeing Co. to acquire 80 airplanes to bolster its aging fleet.

Tehran-based Iran Air, the oldest airline in the Middle East, and Chicago-based Boeing unveiled the landmark transaction—the first between the U.S. and Iran in nearly 40 years—on Dec. 11. In a press release, Boeing said the company “coordinated closely with the U.S. government throughout the process leading up to the sale and continues to follow all license requirements as it moves forward to implement the sales agreement.”