This movie was on TCM recently; I'd missed it in 1948. The action shots were superb in using actual footage from the cameras mounted on fighter planes. There were lots of technical goofs in using P-51's adorned with swastikas to portray the German Airforce and most importantly, there were NO invasion stripes painted on the P-47's during the sequences supposedly over France on June 6, 1944. As a WWII Air Force Veteran, in spite of these omissions -- probably only noticeable to one who was there -- I admired the editing and it was interesting to see some of today's movie & TV stars in minor roles. For movies of that era, "Twelve O'Clock High" was far more technically accurate.
Review of Fighter Squadron
