A versatile and efficient mode of air transport, helicopters are known by numerous names including ‘chopper’, ‘helo’ and ‘heli’. The vertical landing and taking off capabilities of helicopters, make it the ideal type of aircraft, to be used in isolated and congested regions of the world. The first functional helicopter was introduced to the world in 1936. Today, there are numerous types of single-engine and twin-engine helicopters which are used for a variety of purposes including search and rescue missions, air medical service, for offshore support as well as for government operations. The most expensive helicopter in the world is the AgustaWestland AW101 which costs approximately USD 21 million. To have an in-depth insight into the most expensive helicopters in the world, click the link that is given below.