Opinion of Advocate General Pikamäe delivered on 16 March 2021.#Airhelp Ltd v Scandinavian Airlines System Denmark – Norway – Sweden.#Request for a preliminary ruling from the Attunda tingsrätt.#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.#Case C-28/20.