Both the B737-300 and B757-200 that Jet 2 use are some of the oldest around and the average fleet age is greater than most other UK airlines. However, this doesn't imply a poor aircraft as maintenance is the key issue. The problem is passengers will only base their opinions on how shiny the a/c looks and how good the interior is. Ask any of my friends and they'll say most of the Jet 2 fleet is 'past it' - fair or not.