He was a visiting professor in aircraft design at Stanford University and the California Institute of Technology in the United States.
Ljungström made contributions as an engineer in both his family businesses, notably in shale oil extraction, and beyond.
Due to his wide knowledge in the field, he was appointed visiting professor in aircraft design at Stanford University 1966-1967 and the California Institute of Technology 1968, both in the United States.
He initiated the governmental project of wind power in Sweden at the National Swedish Board for Technical Development (Styrelsen för teknisk utveckling) in 1974.
Ljungström has contributed as technical writer and editor in Teknisk Tidskrift (1960-1975), among other publications.