The landings on 6 June did have air support, but for various reasons, this wasn't quite as effective as you'd think. u/davratta and u/Badgerfest discuss why it didn't quite work in this previous post on the matter.

For completeness, we can also look to the naval side of things, ably covered by u/thefourthmaninaboat. Bombardment in general here and here; battleships specifically here; destroyers and small craft here; plus some discussion this thread.