Other aircraft designated as Air Force One have included another Lockheed Constellation, Columbine III, three Boeing 707s, introduced in the 1960s and 1970s, and the current Boeing VC-25As. Since 1990, the presidential fleet has consisted of two highly customized Boeing 747-200B (VC-25A) aircraft. The USAF has ordered two Boeing 747-8s to serve as the next presidential aircraft with designation VC-25B.