DAYTON, OH -- The program executive officer in charge of the Air Force's fighter and bomber fleets said this week his directorate is facing a significant modernization bow wave that is making it difficult to balance aircraft availability with the need for improved capability for an aging workhorse fleet. Brig. Gen. Heath Collins said Sept. 13 that 20 years of flying the service's fighter and bomber fleets without much investment in recapitalization programs has driven a need for significant modernization...