Fear no Herod, Peter Jackson is going to paint those hills in the background a sort of dull drizzly grey colour to represent the sky over Lincolnshire
Then at least some of the images would be real. More likely the Chinese fibreglass Lancasters will be loaned to shopping malls to promote the movie and most of the actual shots will be done with Computer Game Imitation (CGI) or whatever they call it. We've come a long way from the days when they made airworthy replicas even for "Those Magnificent men..."