Complex sentence: Cummings was chosen by producer John Wayne as his co-star to play airline pilot Captain Sullivan in "The High and the Mighty", partly due to Cummings' flying experience; however, director William A. Wellman overruled Wayne and hired Robert Stack for the part.
Split into simpler sentences: Cummings was chosen by producer John Wayne as his co-star to play airline pilot Captain Sullivan in "The High and the Mighty", partly due to Cummings's flying experience. However, director William A. Wellman overruled Wayne and hired Robert Stack for the part.