“The concept of ‘optional price supplements’, referred to in the last sentence of article 23(1) of Parliament and Council Regulation (EC) No 1008/2008 of 24 September 2008 on common rules for the operation of air services in the Community, covered costs connected with the air travel, arising from services, such as flight cancellation insurance, supplied by a party other than the air carrier and charged to the customer by the person selling that travel, together with the air fare, as part of a total price.”
WLR Daily, 19th July 2012
Source: www.iclr.co.uk