Narrative - Official Air Force Mission Description
Another contingent of personnel for HQ 8th Air Force and subordinate commands arrive in the UK. Units arriving in England from the US: HQ 60th Transport Group at Chelveston; 309th Fighter Squadron, 31st Fighter Group, at High Ercall (first mission is 17 Aug); 341st Bombardment Squadron (Heavy), 97th Bombardment Group (Heavy), at Polebrook with B-17s (first mission is 17 Aug).
Source: THE ARMY AIR FORCES IN WORLD WAR II: COMBAT CHRONOLOGY, 1941-1945 by Carter / Mueller, the Office of Air Force History,
Non-Combat Accident Reports
Mission "Strategic Operations" Units arrive in UK June 12, 1942
Primary source for mission statistics: Mighty Eighth War Diary by Roger A. Freeman