May I offer you a warm welcome to the CameraLabs forums.
Having recently had the same issue I'm trying to work out if the horizon needs levelling.
The posts say "No" and the roofs say "Yes". It's something you can do with most picture editing software but it's your call. Do you think that adjusting the contrast and brightness (or playing with "levels") could help darken the sky a bit?
That said, I like the shot. How many people would have seen that shot in their mind's eye when they saw the helicopter? Good work.