Air travel is a form of travel in vehicles such as airplanes, jet aircraft, helicopters, hot air balloons, blimps, gliders, hang gliders, parachutes, or anything else that can sustain flight.[1] Use of air travel began vastly increasing in the 1930s: the number of Americans flying went from about 6,000 in 1930 to 450,000 by 1934 and to 1.2 million by 1938.[2] It has continued to greatly increase in recent decades, doubling worldwide between the mid-1980s and the year 2000.[3] Modern air travel is much safer than road travel.