The 1950s era Boeing B-52 comes with a crew of five (pilot, copilot, weapon systems officer, navigator, electronic warfare officer), and the 1970s/80s era B-1 has a crew of four (aircraft commander, pilot, offensive systems officer, and defensive systems officer. The 1990s B-2 Spirit further reduced this to just two (pilot and mission commander). But how many crew will the incoming Northrop Grumman B-21 Raider have? The short answer is two, but really, this appears to be a trick question with the answer being zero, one, or two pilots.