Four people in Ireland were among 43 arrested at airports across Europe in a crackdown on credit card fraud.
The international operation took place across 38 airports in 16 countries to weed out criminals using fraudulent credit cards to buy flights.
Troels Oerting, head of the European Cybercrime Centre at Europol, which organised the day-long clampdown, said it was targeted at organised crime networks that use the internet to steal people's details.
Mr Oerting said: "This is another great example of the increased co-operation between industry, member states' cybercrime units and the European Cybercrime Centre.
"This close way of working together is key if we want to keep pace with the development amongst organised criminal networks taking advantage of the new criminal opportunities in cyberspace."
Around 200 suspicious credit card transactions were reported during the operation on Thursday, which saw police, Europol, credit card companies and airports pool their resources. Officers were deployed to stop and question individuals attempting to board flights.
Those that were found with airline tickets paid for with stolen credit card details were denied boarding and questioned by waiting police. The arrests in Ireland were made at Dublin Airport. Officers were also deployed in Belfast as part of the operation.
A total of 43 people were detained - seven in the UK, seven in Greece, five in the Netherlands, four in Ireland, four in Spain, four in Germany, three in Austria, three in Lithuania, three in Poland, two in Finland, and one in Romania.
All of those arrested have links with other criminal activities and are being investigated in connection with the distribution of credit card data over the internet, hacking financial institutions' databases and other suspicious transactions. Some are being questioned over other crimes including drug trafficking, illegal immigration and counterfeit documents such as fake IDs.
Peter Bayley, head of fraud at Visa Europe, which collected and transferred financial data back to investigators stationed at the airports during the crackdown, said fraudsters face "increasingly sophisticated methods of fraud detection and control".