Propeller airplanes are able to fly because of one or more spinning propellers that rotate at very high speed, drawing the airplane forward through the air and keeping it aloft because of the force of the air under its wings. Until the advent of jet engines in the 1950s, all airplanes were powered by propellers. Propeller airplanes have the same number of propellers as engines. A small, single-propeller passenger airplane has a single engine while the large bombers used in World War II had four propellers and four engines.
Jets use an entirely different technology than propellers. Rather than being pulled forward through the air as is the case in a propeller airplane, a jet draws air into the engine, compresses it then mixes it with jet fuel which is ignited and blasted out the back of the jet engine at high velocity. Simply put, a propeller airplane is pulled while a jet airplane is pushed. Commercial jet airliners can achieve speeds up to 600 miles per hour. Jet engines were first used on military airplanes in the mid-twentieth century and are now used on all large commercial aircraft.
Passenger airliners are the airplanes that most people are familiar with. DC9s, 707s and 747s are all used to transport passengers between commercial airports. Commercial airliners attempt to balance customer comfort with maximization of profit, resulting in a mixture of movies, snacks and seats that are somewhat smaller than most people would prefer. Commercial airliners utilize the same technology as military airplanes but are designed for stability and safety rather than fighting capacity.
Bombers gained widespread use in World War II to drop many different types of explosive and incendiary devices. Some bombers, such as the B52, achieved tremendous size, with wings spanning 185 feet. Ironically, when fixed-wing aircraft were first developed in the early twentieth century, few people thought that they would have any military value. Airplanes, in the form of fighter jets and bombers, went on to totally redefine the tactics of modern warfare.
Float planes are fitted with large pontoons underneath the body of the airplane so that they can land on and take off from bodies of water. Float planes are primarily used for wilderness travel to access remote areas without airport facilities. The water needs to be fairly calm and flat for a safe float plane landing.
