Executive One is the call sign designated for any United States civil aircraft when the president of the United States is on board. Typically, the president flies in military aircraft that are under the command of the Presidential Airlift Group, which include Air Force One, Marine One, Army One, and Navy One. On December 26, 1973, then-President Richard Nixon became the only sitting president to travel on a regularly scheduled commercial airline flight when he flew on United Airlines flight 55 from Washington Dulles International Airport to Los Angeles International Airport, "to set an example for the rest of the nation during the current energy crisis" and to "demonstrate his confidence in the airlines". Nixon, first lady Pat, daughter Tricia, and 22 staffers, security, and pool purchased 13 first-class tickets at $217.64, and 12 coach tickets at $167.64 aboard the DC-10 on what is traditionally not a very busy flight, and quietly boarded the plane without fanfare in order to maintain security for the flight prior to departure. A Nixon aide carried a suitcase-sized secure communication device on board the plane, so that the President could remain in contact with Washington in the event of an emergency. If the president's family members are aboard, but not the president himself, the flight can, at the discretion of the White House staff or Secret Service, use the callsign Executive One Foxtrot (EXEC1F). "Foxtrot" is the phonetic alphabet designation for the letter "F", with that being the first letter of "family". The military helicopter that normally has the call sign "Marine One" is assigned the "Executive One" call sign when it transports the outgoing president on their final flight from the Capitol, after the inauguration of their successor, as was done on January 20, 2009 for George W. Bush and on January 20, 2017 for Barack Obama. Executive Two Executive Two is the call sign designated for any United States civil aircraft when the vice president of the United States is on board. Typically, however, the vice president flies in military aircraft that are under the command of the Air Mobility Command's 89th Airlift Wing, based at Joint Base Andrews in Prince George's County, Maryland. One notable exception was when Nelson Rockefeller was named Gerald Ford's vice president in 1974. He owned a Grumman Gulfstream II jet that he preferred to the much slower prop powered Convair C-131 Samaritan that was then the