Shortly before Air Force One took off from Turkey at the end of last month\u0027s NATO summit, President Trump secretly slipped away from the presidential jet and was whisked to another plane with the help of an airport catering truck, according to a U.S. official with direct knowledge of the matter.The ruse was employed because the U.S. had learned of a threat from Iran and its allied proxies. U.S. intelligence had detected a credible plot to fire a missile at the plane Mr. Trump was on as he left Ankara, CBS News reported exclusively.The president had expressed awareness of the risks posed by the U.S.-Iran war, calling himself Iran\u0027s "number one target" during the NATO summit.The Washington Post was first to report on the secret plane-switching.\u00a0Multiple Trump administration officials expressed frustration Monday night that highly classified tactics and procedures leaked into the public eye, potentially limiting future protective operations for U.S. presidents.Hours before the move, on July 8, Mr. Trump announced he would leave the Turkish capital of Ankara in the old Air Force One rather than a newer Qatari-donated jet that he had taken to the NATO summit. The president said he was switching planes "for old time\u0027s sake," and U.S. forces stationed at a U.K. refueling stop would be able to check out the new plane, but CBS News has reported that the Secret Service advised that he take the older plane for security reasons.Video footage captured by the press showed the president walking up the stairs of the old Air Force One and disappearing into the plane, with a catering truck visible on the other side of the jet. Several minutes later, the truck pulled away and drove off to another U.S. government plane, which the Post reported was an Air Force C-32A.Mr. Trump then flew from Ankara to a refueling stop in the United Kingdom on the separate plane while members of the press and the president\u0027s staff traveled the same route on Air Force One \u2014 and believed they were on board the same aircraft as the president.\u00a0While in Ankara, members of the press were told to keep the window shades in Air Force One\u0027s press cabin closed, reporters said at the time. Asked why the shades needed to be closed, Mr. Trump later told reporters they were "probably on a dangerous flight because of the sleazebags that we have to deal with."In the United Kingdom, Mr. Trump switched to the newer Air Force One, which was donated by the government of Qatar last year and retrofitted by the U.S. Air Force to serve as the new presidential plane. Mr. Trump spoke to members of the press while they flew across the Atlantic toward Washington, D.C.The Trump administration has never publicly disclosed that the press and some members of the president\u0027s staff were flying on a decoy plane.\u00a0Last month, the new Air Force One \u2014 which debuted in June \u2014 was sent off to be "maxed out" with additional upgrades, the president told reporters, after questions arose about the newer plane\u0027s security features.Asked Monday about the decision to secretly switch planes in Turkey, White House communications director Steven Cheung didn\u0027t respond directly to the question, saying in a statement: "The new Air Force One is a state-of-the-art aircraft that has been fitted with high-level security protocols that ensure the safety of the President and his staff. As the President has said recently, there are many enemies of America who have their sights on him, and we use every tool at our disposal to address those threats."The Air Force has also called the new presidential plane "safe, secure and equipped with the most advanced technologies necessary to meet the requirements of the presidential mission."