Low-cost airline Wizz Air has been ordered to refund thousands of passengers after a court ruled that 111 clauses in their 'customer contracts' were in fact unlawful.

Austria's Supreme Court or 'Oberster Gerichtshof' (OGH) said a number of policies for their countries passengers, including a 40 Euro fee for airport check-ins and a 12-month time limit for vouchers, were unfair.

The legal ruling comes after Austria's Chamber of Labour or 'Arbeiterkammer' (AK) won its case against the Hungarian airline - including that the budget carrier's practice of refunding ticket costs in 'Wizz credits' without the written consent of passengers were unlawful.

While Austrian judges criticized several hidden fees contained in the airline's general terms and conditions as well as non-transparent and difficult-to-understand contractual clauses.

And the obligation for customers to assert compensation claims exclusively via the Wizz Air website or a fee-based call centre was also declared inadmissible.

Now all Wizz Air airport check-ins paid in Austria since 2018 will be refunded - while expired 'Wizz Credit' vouchers will be replaced with new voucher codes valid for five years.

The policy changes and refunds affect all passengers resident in Austria and are valid until at least December 31st 2027.

It's not believed the Austrian court ruling will immediately affect UK passengers - although it may lead to other European courts looking more closely at other budget airlines' consumer clauses.

Wizz Air is one of the largest low-cost airlines in Europe and launched an aggressive expansion strategy in Vienna in 2018.

Wizz Air said it accepted the court ruling, adding: "Following discussions with the Austrian Chamber of Labour, Wizz Air has reached a settlement to resolve the issues raised in the legal proceedings.

"The airline acknowledges and accepts the recent rulings of the Vienna Commercial Court and will act accordingly.

"As part of this agreement, Wizz Air has set up a refund process for passengers who have been charged an airport check-in fee since 1 January 2019 and will restore or refund expired WIZZ Credits and reissue expired WIZZ Vouchers with a five-year validity.

"Wizz Air has also set up a dedicated refund page for affected customers and remains committed to ensuring transparency and compliance while continuing to offer affordable travel options."

In Britain, Wizz Air UK is deemed the second most punctual airline but has also been criticised by Which? after some negative responses in the consumer watchdog's annual airline satisfaction survey.

Wizz Air UK flies directly to 50 destinations from several airports, including London Gatwick and London Luton.

This week Wizz Air UK announced it will be the first airline to offer a direct flight from Gatwick to Medina in Saui Arabia, launching on August 1st, using the longer-range Airbus XLR aircraft.