Concerned about relying upon commercial airlines to transport the president, officials of the United States Army Air Forces, the predecessor to the US Air Force, ordered the conversion of a military aircraft to accommodate the special needs of the commander-in-chief.[11] The first dedicated aircraft proposed for presidential use was a C-87A VIP transport aircraft. This aircraft, number 41-24159, was modified in 1943 for use as a presidential VIP transport, the Guess Where II, intended to carry President Franklin D. Roosevelt on international trips. Had it been accepted, it would have been the first aircraft to be used in presidential service.