Complex sentence: Civil operations were largely abandoned at both Nutts Corner and RAF Aldergrove during the Second World War when it became an important RAF Coastal Command station and was also used as a transport hub for aircraft arriving from the United States.
Split into simpler sentences: Civil operations were largely abandoned at both Nutts Corner and RAF Aldergrove during the Second World War. During World War II it was an important RAF Coastal Command station and was also used as a transport hub for aircraft arriving from the United States.