The paper provides a legal analysis of the terms “extraordinary circumstances” and “strike” as given in the Regulation (EC) Nr 261/2004. The author focuses on relation between art. 5.3 and recital 14 of preamble to the EU act. Deliberations lead the author to conclusion that strike of air carriers employees could not be interpreted as a exoneration clause by which the carrier may escape liability for passengers claims. An appropriate interpretation given by Court of Justice of the European Union or an amendment to the Regulation (i.e. proposal of legal definition) seem to be crucial, in particular from the point of view of consumers protection.