Thomas began his professional career with Bell Labs and then went to RCA to work on defense research and development projects. This led to work with the State Department, and he served in both Beirut and Frankfurt before returning to Washington, D.C., to be in charge of research and development and then to work for private firms doing defense contracts and security consulting.
Returning to government service, Thomas worked with the Immigration Service and the Customs Service before retiring and moving to Charlotte, Vt., in 1993. Thomas married Patricia Smith in 1974, and she died in 2008. They had no children. Thomas died Jan. 7, 2017, in Burlington, Vt.