Interplanetary spaceflight is travel on one planet.
 Humankind has come a long way in transportation since Christopher Columbus sailed to the New World from Spain in 1492, an expedition which took over 10 weeks to arrive at the final destination; to the 21st century when aircraft allows travel from Spain to the United States overnight
 A prime example of this are the two crafts of the Voyager program, which used slingshot effects to change trajectories several times in the outer Solar System

