Complex sentence: The Royal Air Force's Strike Command was the military organization which controlled the majority of the United Kingdom's combat aircraft from 1968 until 1 April 2007 when it was merged with Personnel and Training Command to form the single Air Command.
Split into simpler sentences: The Royal Air Force's Strike Command was the military formation which controlled the majority of the United Kingdom's combat aircraft from 1968 until 1 April 2007. That day it was merged with Personnel and Training Command to form the single Air Command.