But read the reasoning of the Court (in particular at paragraphs 39 to 43. The "wildcat" character of the strike was not relevant. What was relevant was that the strike was about an issue that is part of the normal process of running the business and could, as a matter of course, employers may give rise to disagreements or conflicts with employees.

I struggle to see how, in the light of that judgment, a strike over wages could possibly be regarded as constituting an extraordinary circumstance. To paraphrase the court, the determination of rates of pay by undertakings are part of the normal management of those entities. Thus, air carriers, may, as a matter of course, when carrying out their activity, face disagreements or conflicts with all or part of their members of staff. Therefore, the risks arising from the social consequences that go with such measures must be regarded as inherent in the normal exercise of the activity of the air carrier concerned.

Paragraph 46 is also significant: the court says "That finding is not called into question by the fact that the social movement should be regarded as a ‘wildcat strike’ within the meaning of the applicable German social legislation, as it was not officially initiated by a trade union." What the Court is telling us here is that even if it is a wildcat strike, it makes no difference. This imo implicitly makes it clear that its conclusion would a fortiori have been the same if the strike had been an official one.