If it's any consolation, it happens both ways! No matter what seat you sit in there will always be someone who either just can't relinquish control or can't relax unless they are doing the work.
Zerozero's suggestion is one good way of dealing with it, although it would be a competition to see who's patience snapped first! If you get to the point where you really have to say something, bite your tongue and count to five to make sure you say something reasonable and productive. F%&k off you T£&t! may get a result but it may not help in the long run!
Something else to bear in mind is why are they like that? New to the job and trying to impress with their supersonic scan? New and nervous? It may be they are just born irritating! Best to wait until you're on the ground and ask them if they realise what they are actually doing.