A good story (spoiler).

I enjoyed this film which illustrates the plight of Norway during WWII.
I realise that allowance has to be made for the propaganda intended at the time of release but I have a few questions regarding the attack on the German airfield in the second half of the film:

Would the operation have been worthwhile as a military incursion? An RAF bombing raid would have achieved the same result.
How did the troopship get in and out of the fjord without the earlier attention of the Germans? I know it was high tide on the way in but it would have been high and dry on the way out.
I noticed when the British attacked the German airfield they appeared to blow up a couple of Lysanders and what looked suspiciously like a Blenheim. Perhaps captured in a previous attempt to pick up British or Norwegian agents.