In the following decade the need for air transportation made it very desirable. This is mainly due to World War I as many of the retired bombers were converted into commercial airliners. Soon after these flights began it became apparent that in order to make financial gains again it was necessary for there to be more people on these planes as they initially accommodated four passengers (Century of Flight 2008). The British airline de Havilland built a ten-passenger plane that sat its occupants comfortably called the de Havilland Dragon. The 1930s saw the expansion of the commercial airliner market (Century of Flight 2008). As the need for air transportation has grown, so has the supply, as with any demand. Struggling airlines such as Lufthansa (Germany), United Airlines (United States), Imperial Airways (Great Britain) and KLM are just some of the airlines that have started operating in this