The board of directors at General Dynamics, parent company of Gulfstream Aerospace and Jet Aviation, announced yesterday that chairman and CEO Jay Johnson will retire effective December 31. Johnson, the former Navy fighter pilot who’s been heading General Dynamics since 2003, is to be succeeded by Phebe Novakovic. Last month, Novakovic was named president and COO of General Dynamics. Previously she served as executive vice president of the company’s marine systems group and senior vice president for planning and development.