After 14 months as COO of U.S. operations for Jet Aviation, Jim Ziegler is leaving the company but will retain an advisory role. A 1979 graduate of Wichita State University, Ziegler spent 23 years at Learjet and Bombardier, including stints as president of Bombardier Aviation Services and vice president and general manager of Bombardier’s Learjet manufacturing operations. Ziegler was running a consulting business when he joined Jet Aviation on June 1, 2007. According to Jet Aviation, Ziegler is credited with leading capacity expansions and improvements at subsidiary Midcoast Aviation’s St. Louis facility and helping acquire maintenance and completions company Savannah Air Center. Gary Dempsey and Kurt Sutterer take over responsibility for Jet Aviation’s U.S. operations. Dempsey is president of flight services for the Americas, and Sutterer is president of MRO and completions at Midcoast Aviation, Jet Aviation’s U.S. aircraft maintenance and completions division. General Dynamics acquired Jet Aviation last November from Permira Funds, which bought the company in 2005.