Litton division presidents John M. Leonis, Thomas J. McGuigan and Allen E. Powers have been elected corporate vice presidents. Leonis is president of Litton's guidance and control systems division, Woodland Hills. McGuigan is head of Litton Systems Canada Ltd., Ontario. Powers is in charge of Litton's data systems division, Van Nuys. All three divisions are units of Litton's advanced electronic systems group. Litton Industries is based in Beverly Hills.