So how did the Allies seek to apply their air power in Normandy? In the event, it was largely dispersed along the line of battle, rather than concentrated at decisive points. Allied Tactical air power was a powerful but a blunt instrument. The senior commanders in both the army and RAF lacked a clear vision of how to apply their overwhelming airpower.
So why did 2nd TAF, in a sense, lose the bubble, or at least stray from their own professed doctrine? Firstly, it was engaged in a desperate battle, in which desperate measures were resorted to. Secondly, Montgomery did not shine in this campaign, and is himself often criticized for lacking a general plan that worked towards operational level concepts. Small wonder then, that the targets 2nd TAF was directed against were generally not operational level in nature. Finally, air support doctrine was not really fully developed (as arguably army doctrine for mechanized operations was not).
Because of the all-consuming Army/RAF arguments over air power and strategic bombing, neither side gave much serious thought to operational air support to a land campaign. When it was finally decided, very late in the day, to form tactical air forces for just this role, all of the available energy was consumed by frantic efforts to knit together a working organization and solve the immediate practical problems. This was an extraordinary technical success, but it left no time or energy for contemplation of the more subtle -- and difficult -- doctrinal questions, ie where to concentrate the air effort? What sort of target is most important?
Fortunately, the Western Allies enjoyed such overwhelming air supremacy that this dispersal of effort was not critical, and the campaign was in the end successful. Given the near run nature of that success, all of the Allied contributions were critical. 2nd TAF unquestionably succeeded in helping defeat the German armies in the West. Although a blunt instrument, it was a powerful one.