Case C-28/20: Judgment of the Court (Grand Chamber) of 23 March 2021 (request for a preliminary ruling from the Attunda tingsrätt — Sweden) — Airhelp Ltd v Scandinavian Airlines System SAS (Reference for a preliminary ruling — Air transport — Regulation (EC) No 261/2004 — Article 5(3) — Common rules on compensation and assistance to passengers in the event of cancellation or long delay of flights — Exemption from the obligation to pay compensation — Concept of ‘extraordinary circumstances’ — Pilots’ strike organised within a legal framework — Circumstances that are ‘internal’ and ‘external’ to the operating air carrier’s activity — Articles 16, 17 and 28 of the Charter of Fundamental Rights of the European Union — No impairment of the air carrier’s freedom to conduct a business, right to property and right of negotiation)