WASHINGTON (Reuters) -Before strapping into the cockpit of the U.S. Air Force's B-2 Spirit stealth bomber for missions that can stretch beyond 40 hours, pilots undergo weeks of preparation that focuses not only on flight plans, but what to eat. The B-2, a $2 billion flying wing built by Northrop Grumman, played a key role in delivering strikes on Iran's nuclear sites on Saturday. "We go through sleep studies, we actually go through nutritional education to be able to teach each one of us: one, what wakes us up and then what helps us go to sleep," said retired Lt. Gen. Steve Basham, who flew the B-2 for nine years and retired in 2024 as deputy commander of U.S. European Command.