Financial instruments - Fair value and risk management - Change in gross value used for calculating hedge ineffectiveness (Details) - Cash Flow Hedges - EUR (€) € in Millions	12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Disclosure of detailed information about hedging instruments [line items]
Change in gross value used for calculating hedge ineffectiveness	€ (2,427.7)	€ 418.7	€ (1.5)
Foreign currency risk \| Property, plant and equipment - aircraft additions
Disclosure of detailed information about hedging instruments [line items]
Change in gross value used for calculating hedge ineffectiveness	(13.4)	149.8	515.0
Foreign currency risk \| Fuel and oil operating expenses
Disclosure of detailed information about hedging instruments [line items]
Change in gross value used for calculating hedge ineffectiveness	(14.4)	114.6	(117.7)
Commodity price risk \| Fuel and carbon operating expenses
Disclosure of detailed information about hedging instruments [line items]
Change in gross value used for calculating hedge ineffectiveness	€ (2,399.9)	€ 154.3	€ (398.8)

The gain (loss) on the change in fair value of the hedged item used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item.