(AP) – President Donald Trump flew aboard the older Air Force One on Wednesday for his trip from Turkey to the United Kingdom, opting not to use the Boeing 747 donated by Qatar that recently entered presidential service.

Trump said he chose the older aircraft “for old time’s sake” and explained that the Qatari jet would travel separately to RAF Mildenhall, where U.S. military personnel would have an opportunity to view it.

The decision came as questions continue over the Qatari aircraft, which was refurbished to serve as a temporary presidential plane while Boeing completes two long-delayed replacements for Air Force One.

The aircraft has sparked criticism from some lawmakers and aviation experts, who have raised concerns about the expense of modifying the jet, the accelerated timeline for completing the work and its security. Air Force officials have maintained that the aircraft meets the requirements for presidential travel.

When asked whether concerns about potential threats influenced his decision to switch planes, Trump did not directly answer. He instead told reporters he believes Iran considers him a top target, adding that he was not concerned.

The Qatari jet is expected to remain in service until Boeing delivers two new presidential aircraft, a program that has been delayed several years and is currently projected for completion no earlier than 2028.