I've had a great affection for this film since I first saw it on tv, in the 70's. In my youth, I found it to be quite exciting and it spawned a lifelong interest in airships. The performances are good and the effects are good for their time and don't come across as too dated. The story is a bit murky. We never really feel that Michael York is that torn between his loyalties; rather, he seems more like a spy determined to perform his mission. His actions seem more motivated towards convincing the Germans that he believes in what they are doing, rather than being conflicted. The romantic angle is also a bit weak. It comes across more that York is fascinated with Elke Sommer, but not necessarily in love. She does not trust hims, nor does she seem attracted to him. It comes across as too ambiguous.
As far as the commando mission, it is an interesting idea, although the idea of a commando assault in the days before automatic weapons comes across as a bit absurd. Watching the German raiders trying to swing their rifles (with bayonets affixed, no less!) in enclosed spaces is a bit much. It is not impossible that a zeppelin could carry a raiding party. In the first place, it is only a squad that is taken aboard, not a battalion. Secondly, the zeppelin is not carrying a bomb load. Thirdly, the squad is taken aboard near Norway, and is not carried over the entire voyage; only after fuel has been used up. The logistics are sound; the motive for the attack may need some analysis.
The idea that the British would give up, due to the destruction of the Magna Carta and the crown jewels is a bit absurd. However, the thought that German soldiers could strike on British soil, and destroy national treasures, would be a great blow to British morale. World War I was not a very popular war in many circles in Britain. The stalemate in the trenches and the bombing raids on Britain had many people feeling that the war was a waste. A raid such of this would have at least caused the British to pull back some of their resources to defend their home, thereby weakening the front. It's an interesting possibility.
All-in-all, this is an entertaining film with fine performances. The flying sequences are quite well done. The plot is intriguing, if not wholly satisfying. Well worth a look.
