'In the case that you are unable to select your preferred airport, please note that the limit has been reached and Wizz Air is unfortunately unable to offer you a Wizz All You Can Fly membership at this time.

'The terms and conditions document on Wizz Air's website also warns that seat availability is not guaranteed for membership holders and would depend on 'several external and internal factors.

' Leading UK consumer group Which? has also named the airline as the worst performing for its customer service.

This month, Hungary's competition authority imposed a **770,000 euro** fine on Wizz Air for misleading communications, including how it encouraged customers to purchase more expensive travel packages.

Wizz Air told BBC News it 'questions the legality of the fine, disagrees with its reasoning, and is taking legal action.

' Additionally, in August, Wizz Air reported a **44% drop** in first-quarter operating profit and cut its profit forecast for the year as a whole.