This year marks the 50th birthday of the 737. The 737 was the first single aisle jetliner, that was made specifically for the short to medium range market. Over the years since its introduction into service in 1967. There have been over 9000 deliveries and there have been 3 generations of it improving upon the prior generation. This plane has transform the airline industry and has made low cost carriers such as Southwest and Ryanair and made the industry more competitive. As of 2006 experts say that over 1000 planes are airborne at any given time. Today, many experts say that the 737 is one of the most successful airliner in history.