WASHINGTON: Before strapping into the cockpit of the US 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. It demands extraordinary endurance from its two-person crew. That starts with understanding how nutrition affects alertness and digestion during intercontinental flights that can span nearly two full days.