The airline industry was hit particularly hard after the 9/11 attacks on the World Trade Center in 2001. In 2002, Southwest Airlines, one of the healthier airline companies, decided to lengthen the useful lives of its aircraft from 22 to 27 years. Shortly thereafter, following Southwests lead, other airlines made the same move.
(a) What advantage, if any, did the airlines gain by making this change in estimate?