Airplane is a fixed-wing aircraft that is propelled forward by a propeller or a jet engine. There are commercial airplanes, private or business airplanes, cargo airplanes, and military aircraft.
Commercial airlines began in the 1920s. Douglas DC-3 was one of the aircraft which had a lasting effect on the airline industry during the 1930s and 1940s. All airlines want to increase the flight velocity and reduce the time of flight between the airports. Flight velocity of aircraft is measured through Mach numbers. Mach number is the velocity of the aircraft to the velocity of sound. Mach one tells that speed of aircraft is equal to the speed of sound.
Commercial aircraft at present fly at Mach number of around 0.7. Fighter aircraft can fly above Mach 1. Concorde is the first supersonic commercial passenger transport aircraft. The aircraft is an engineering marvel but produced noise and was expensive for operation. The aircraft had a maximum flight speed of twice the speed of sound of around 2.04. However, due to economical viability, the airliner was grounded in 2003.
However many aerospace companies are trying to bring back supersonic passenger aircraft. Supersonic aircraft’s advantages is that it highly reduces the flight time between cities. However, there should also be an economical feasibility. Some aerospace companies like Boom, Aerion Supersonic and Spike Aerospace are developing supersonic passenger planes.
NASA and Lockheed Martin’s X-59 QueSST airplane is Quiet Supersonic Technology airplane, which is targeted to make its first flight next year. Some aerospace companies like Boeing and Reaction Engines Limited are also working on the development of hypersonic airplanes, that will have a Mach number of more than 5. New technologies, materials, and airplane design can make that possible in the near future.