United States Air Force chief scientist Mark Lewis spoke to Flight at the 15th American Institute of Aeronautics and Astronautics' space planes, hypersonic systems and technologies conferences held in Dayton, Ohio from 28 April - 1 May 2008. In his role he is chief scientific adviser to the USAF chief of staff and secretary of the air force, and provides assessments on a wide range of scientific and technical issues affecting the service's missions.