 The authors predict that sharper rises in passenger numbers in developing countries will fuel demand for both Neo and Max models, but also, importantly, current-generation aircraft as airlines seek to add capacity but find themselves at the end of long lines for the new models.Both Airbus and Boeing currently have record-high order backlogs, making the second-hand market an appealing option for fast-growing carriers.In March 2015, Avolon published an updated analysis of the key factors that influence the economic life of commercial jet aircraft building on the analysis issued in September 2012.