Aashna Shroff, personal finance expert at money.co.uk, comments:
"Ryanair hasn't helped its customers by leaving the High Court appeal until the very last minute, but it claims now there will only be 'small delays' tomorrow.
"I would advise travellers to check the Ryanair website and to contact their travel providers for up-to-date information on flights tomorrow and Friday.
"It's important to check this information before travelling to the airport to ensure you know the latest status of your scheduled flight and you're not left waiting unnecessarily at the airport.
"If you experience a significant delay when you're at the airport - whether flying from or to the UK - the airline is required to make your wait a comfortable one, including providing food and drink, phone calls, and even accommodation, if necessary.
"If your flight is delayed by three hours or more, you are entitled to a cash payment of 250 Euros for short flights and 400 Euros for a flight distance of 1,500 to 3,500km.
"If you are delayed by more than five hours, you have the right to cancel your journey and have the cost of your flight reimbursed - which won't be much of a consolation to those people who have already paid for accommodation and other costs at their holiday destination.
"In the unlikely event that your flight to or from the UK is cancelled, thanks to EU regulations, you are entitled to: a full refund; or an alternative flight to your destination from a nearby airport, with the airline responsible for additional travel costs; or an alternative flight on a later date outside the strike period.
Can I claim anything on my travel insurance?
"You can't claim for your cancelled flight on your holiday or travel insurance as the airline will offer a refund or alternative booking. However, your insurance should cover any other losses, such as missed hotels, car hire or train tickets.
"This will depend on your travel insurance provider's policy on cancellation due to strike action and the level of cover you have in place. Some travel insurance providers will only pay for claims on policies that are purchased before the actual strike dates were announced.
"This will be stated in the terms and conditions of your travel insurance policy. If you are unsure, contact your insurer to find out what is covered under your travel insurance for airline strike action."