https://online2.tingclass.net/lesson/shi0529/0009/9692/106.mp3
https://image.tingclass.net/statics/js/2012
The average age of the fleet of the seven large U.S.passenger airlines is about 14 years old, according to The Airline Monitor.
It found American and Delta/Northwest had the oldest fleets, at about 16 years on average.
