Complex sentence: Almost immediatley, the United States Army Air Force IX Engineering Command 820th Engineer Aviation Battalion cleared the airport of mines and destroyed Luftwaffe aircraft and Rennes Airport became a USAAF Ninth Air Force combat airfield, designated as "A- 27" about 10 August.
Split into simpler sentences: Almost immediatley, the United States Army Air Force IX Engineering Command 820th Engineer Aviation Battalion cleared the airport of mines and destroyed Luftwaffe aircraft. Subsequently, Rennes Airport became a USAAF Ninth Air Force combat airfield, designated as "A- 27" about 10 August.