Two weeks ago Boeing rolled its 8,000th 737 off the line and delivered it United Airlines, who was the first airline ever to order a 737. This is a great demonstration of how successful the 737 program has been. When Boeing first implemented the program in 1967 it was another seven years before Airbus delivered their first aircraft. This got me to thinking about how old are the airplanes we fly on? What is the average age of airline fleets in the US and how their age affects the passengers experience?