By Glenn Pew for AVweb.com Boeing has flown a manned aircraft on hydrogen fuel cell power. The full text of Boeing’s release follows: MADRID, Spain, April 03, 2008 — Boeing [NYSE: BA] announced today that it has, for the first time in aviation history, flown a manned airplane powered by hydrogen fuel cells. The recent milestone is the work of an engineering team at Boeing Research & Technology Europe (BR&TE) in Madrid, with assistance from industry partners in Austria, France, Germany …