Meanwhile, President Trump welcomed Polish President Andrzej Duda to the White House Wednesday, signing a military agreement to station an additional 1,000 U.S. troops in Poland. Their announcement came as the U.S. Marine Corps executed a rare flyover of an F-35 stealth fighter jet over the White House as Presidents Trump and Duda looked on from the South Lawn. Trump said Poland had agreed to purchase at least 32 of the Lockheed Martin jets. The F-35 program has been marked by multibillion-dollar cost overruns, with the Pentagon’s own estimates putting the cost of maintaining the jets at nearly $1.2 trillion in the coming decades.