If the presidential race were to go to the candidate with the fastest plane, Republican George Bush would leave Democrat Michael Dukakis in his jetstream. One only need to hear the nickname of the Dukakis plane _ ``Sky Pig'' _ to get the general idea. The name comes partly from the bloated look of the aircraft, a stubby 20-year-old Boeing 737, but mostly the description is based on flying time: It takes the plane seven hours to cross the country _ a 4{-hour flight on most commercial airlines. Method of travel is just one of many contrasts of day-to-day life on the campaign trail for the two men who would be president. Because he's the vice president, Bush gets to draw from a fleet of fast Air Force planes hangared at Andrews Air Force Base near Washington. As any plane the president flies automatically becomes ``Air Force One,'' whatever plane Bush is on becomes ``Air Force Two.'' Usually a converted Boeing 707 or a McDonnell-Douglas DC-9, Bush's planes are fast, meticulously cared for and flown by Air Force pilots. Bush's campaign reimburses taxpayers, in part, for the use of the plane, which is blue and white with the words ``The United States of America'' emblazoned across the sides. Dukakis' plane, chartered from Presidential Airlines, is the same aircraft that Bush's former rival, Kansas Sen. Bob Dole, used. Designed for short-range flying, ``Sky Pig'' cannot cross the country without one or more refueling stops. That was fine for the kind of campaigning Dole did during the GOP primaries _ after all, Dole used to joke that he'd fly over a state and direct the pilot to land wherever he spotted a crowd _ but it poses some scheduling problems in the final weeks of a national campaign. Aides to Dukakis, however, say the candidate is comfortable with the plane, likes the ``Presidential'' designation on the side in green letters, and has no plans to trade it in for a sleeker model.