Complex sentence: Operations against Kenley, Biggin Hill, North Weald and Hornchurch had the potential to destroy 11 Group's major sector stations and impair its defences, but it would also draw the defending fighters into battle.
Split into simpler sentences: Operations against Kenley, Biggin Hill, North Weald and Hornchurch had the potential to destroy 11 Group's major sector stations and impair its defences. It would also draw the defending fighters into battle.