Passengers of airlines including easyJet and British Airways are being urged to claim millions of pounds worth of travel vouchers before they expire.
International Airlines Group - the parent company of BA, Iberia, Aer Lingus, Vueling, and LEVEL - is estimated to still be sitting on around €600million (£533million) in vouchers issued during Covid.
Figures suggest easyJet still has around £110million in unclaimed vouchers.
Aviation consultant and former IAG employee Robert Boyle flagged the figures to the BBC and explained how the vouchers were issued when airlines were forced to cancel a huge number of flights during the pandemic.
Both companies have extended the expiry date of their vouchers a number of times.
EasyJet said no vouchers had expired yet, while British Airways run out in September 2023.
EasyJet told the BBC that the expiry date had been extended "to ensure customers have the maximum opportunity to utilise their vouchers".
The airline said the number of unused vouchers at the end of its last financial year on September 30 equated to around £110million.
Easyjet said this was around 2% of its overall revenue for 2019 and that there was a " "very small proportion of customers who have not yet used their vouchers".
In its statement to the BBC, it added: "And it is also worth noting that the number will have reduced since then as five months have passed - including a busy booking period at the turn of year."
British Airways told the BBC it was "always reviewing" this date.
It also said 700,000 vouchers were used last year and it was sending reminders to customers who hold outstanding ones.
During the Covid-19 pandemic, many airlines controversially started to issue travel vouchers rather than cash refunds for travellers whose flights had been cancelled.
Travellers then claimed that these vouchers were difficult to claim and use for future flights.
The Civil Aviation Authority, the UK regulator, criticised airlines for its initial response to the pandemic including a backlog of refund claims in 2020.
It said the process did improve as airlines recovered as the crisis wore on.
How to claim a travel voucher
If your flight was cancelled by the airline due to Covid-19 restrictions, and you opted to receive a voucher, then you will have been contacted about it by your airline.
According to the easyJet website, you should be able to find your voucher by searching through your email inbox by searching for the term "flight voucher", "easyJet voucher" or the booking reference of the disrupted flight your voucher was issued for.
The airline also said passengers should check their junk and spam folders for the email account registered for the booking cancelled.
British Airways website also states that those who were affected will have already been contacted and sent their voucher to the email address registered with the booking.
The airline also has an online tool which can help if you are unsure whether you have an e-voucher or you are unsure of the amount left on it.
All you need to enter is your email which would be linked to the booking.
You can find this tool here.
