Nike system requirements in the new atomic and jet age Conclusion Most Aircraft Reached their Targets in World War II During the 1942 Japanese conquest of Manila in the Philippines, the Japanese planes simply flew higher than the maximum vertical range of the United States anti-aircraft guns. Many people felt that since the guns had no effective pointing system against aircraft targets, the Japanese planes could have flown anywhere quite safely. Also see a Pearl Harbor story This anti-aircraft situation was typical. Ground fire against aircraft looked impressive, but downed few planes. Air crews probably felt that a 10 percent loss was very high - but defenders took a pounding.
Author gets flack.
Several people felt the above is not strictly true. They point to the very successful air defense of the Normandy landing areas in June of 1944. One report says that 11,000 Allied aircraft were involved with the Normandy invasion. Yes, there were few reports of German aircraft. One British fighter wing history reports that the Germans mounted about 100 sorties, but does not mention combat with them.