The highly classified B-21 Raider took its first flight on Friday and there was nothing secretive about it. The aircraft took off from Palmdale Airport in California on a bluebird day with hundreds of people watching from the roads ringing the airport. The stealth bomber that will eventually replace the B-2 Spirit is optionally piloted and employs numerous system and cloaking technologies designed to overcome the advances in detection technology that have eroded the B-2’s strategic advantage over its 20 years of service. The Air Force is planning to buy 100 B-21s, which are estimated to cost $700 million each. The overall program cost will be about $200 billion.