"Aeronautical" refers to anything related to the design, development, and study of aircraft and flying objects, like planes, helicopters, and spacecraft. Full definition
He put to good use the studies of aeronautical engineering from school and is unanimously regarded as a master of aerodynamic design — remember, there were no computerized simulations in the late 1960s and wind tunnels for automobiles were in their early, experimental days. (drivemag.com)
From 1965 to 1977 he was a professor of aeronautical engineering at the Pennsylvania State University. (desmogblog.com)
After picking up a degree in aeronautical engineering from California Polytechnic in 1965, he took a job as a test engineer at Edwards Air Force Base in the Mojave. (inc.com)