Northrop Grumman remains on track for a flight test of the Air Force's B-21 Raider later this year and is anticipating a low-rate initial production purchase of five of the bombers, executives said during the company's year-end earnings call Thursday. Northrop has kept costs under the Air Force’s independent cost estimates for B-21, CEO Kathy Warden said, which was $550 million per unit in 2010 dollars or $692 million for 2022 dollars. The expected purchase would be the first of...