Things could have been 'turned' had the LW persevered on attacks against the Radar sites and RAF early and often... having said that the purpose was to achieve air superiority over England to support an invasion, and its not clear how Hitler was going to invade.... God knows Crete didn't work out, or any other Island that I am aware of.
Even with relative air superiority over the Channel and England, attempting to transport troops from France to England remained a LARGE question of 'how'?