Sitting among the C-5Bs on the flightline at Westover ARB, Massachusetts, is a VC-25A used for presidential transport. The aircraft was flown without passengers to Westover after dropping off President Barack Obama in New York City on 19 September 2011. The two VC-25s, the military variant of the 747 passenger airliner, are assigned to the Presidential Airlift Group, a part of the 89th Airlift Wing at Joint Base Andrews, Maryland. The VC-25A is commonly known as Air Force One, although that call sign is reserved for any Air Force aircraft when the president is aboard.