I had a friend (now deceased) who was in a 16 plane formation which attacked a German position on D-Day.
He said the anti-aircraft fire was extremely accurate. Of 16 B-26s which went in, only 9 came out. He said he lost an engine. He was returning to England with the one engine when a Spitfire came alongside. It stayed with him until he landed.
The Air Force strongly opposed precision CAS back then and apparently still does but pinpoint delivery of 500 pound bombs really can't be beat for reducing even the strongest enemy positions.
General MacArthur got around the Army Air Force by using Marine Corps SBDs with Marine FACS controlling them and wiped Japanese defenses off the map as they were encountered.
It is true that German antiaircraft fires were ferocious but they could have been dealt with using a sort of "Wild Weasel" tactic using P-47s or P-51s to cream the FLAK positions and the SBDS/A-36s to accurately bomb those bunkers and trenchlines overlooking Omaha.
Could have saved a lot of lives. It's a shame that the USAAF couldn't have done that. It's an Air Force cultural thing that needs to be restructured: groundpounders have families too.