STRATFORD - A high-performance aviation center is taking off at the Sikorsky Memorial Airport in Stratford. The company, called Rivetborne, was started by Air Force pilots and aerospace engineers who say they want to give civilians the experience of military flight. The program began back in January. Owner Gemo Yesil, a United States Air Force pilot and member of the National Guard, says he wants visitors to leave with a fresher outlook on the aviation industry.