At the end of Chapter 20, what happened when Patton's single-engine L-5 Sentinel was flying to Patton's headquarters?

Patton was flying to his headquarters in his L-5 Sentinel. The plane at certain angles had a resemblance to the German Fi-156 Storch. Suddenly a Spitfire with the markings of the British Roy Air Force attacked. Patton's plane had no weapons. The Spitfire fired and missed on the first pass, but nearly hit the L-5. The pilot assigned to Patton began defensive maneuvers. The Spitfire came in for another shot, but it was too low to the ground, and it crashed. It was speculated whether the attack was a case of mistaken identity or an attempt to murder Patton.