Is the destination of a commercial flight important for the pilot? As has been recently advertised (in here, here, here also), a recent British Airways flight from London City Airport destined for Düsseldorf mistakenly flew its passengers to Edinburgh instead.

I'm a layman in terms of aviation, but I (and I'm sure many more do) do see aviation as a strictly regulated area full of double-checks, double instruments (even 2 pilots!) to make sure an airplane is doing exactly what it's supposed to be doing.

Perhaps mine is a rather car-centric view, but I can't imagine starting the engine of the car without knowing clearly where I'm heading, which landmarks, roads (and so on) I'm supposed to pass by during the route.

TL;DR:

Must (or should) both pilots know where he airplane they are flying is going to? Or do they simply follow an approved flight path?
The pilots in this case did know where they were going: Edinburgh.

BA said a paperwork error was to blame, with the pilot following orders from Germany, where WDL’s head office had filed the incorrect flight plan.  The pilots flew according to the flight plan they were given, and ATC happily routed their plane along that flight plan as well.  The pilots had no reason to suspect the flight plan was incorrect, and safety was never compromised.

The dispatchers involved could use improvement, though.