It sounds like 45 inherited this deal from 44, as it was signed in Nov 2016, and that there is also another order for a different type of plane that has yet to be fulfilled.
It just seems like it’s another mess Obama left behind.
(And I apologize in advance for my ignorance as I know NADA about the subject, but thank you for the article share).
Trump certainly has the authority to cancel the deal (signed by Obama in November 2016 or not) after the fact - it has been done before. It is clearly an issue representing incoherence in his White House that he did not cancel the deal.
Mattis seems to be running things on his own, unsupervised or controlled by the White House. He also seems too deeply in bed with the Saudis and the Gulf States which are none of them our true friends, no matter what Iran is up to and no matter how much the Mullahs in Tehran will also never be our friends.