"the world's most expensive fighter jet"

Some of the nation's top aviators are refusing to fly the radar-evading F-22 Raptor, a fighter jet with ongoing problems with the oxygen systems that have plagued the fleet for four years.

At the risk of significant reprimand — or even discharge from the Air Force — fighter pilots are turning down the opportunity to climb into the cockpit of the F-22, the world's most expensive fighter jet.

http://www.latimes.com/business/la-fi-fighter-pilots-20120502,0,1192307.story