Passengers should allow up to three hours for their return flight to the UK due to border delays,an airline boss has warned (Picture: AFP)

Holidaymakers should allow several hours before their return fight to the UK,an airline boss has warned.

Passengers are facing delays at borders due to the implementation of the EU’s Entry Exit System (EES).

Wizz Air UK director Yvonne Moynihan said some travellers were missing flights after getting held up at passport control while leaving several European countries.

Under the new scheme,passengers from third countries entering and leaving the Schengen zone are required to provide fingerprints and facial biometrics.

Some 80 million people have been recorded entering or leaving under the system since it was introduced last October.

The scheme was supposed to be fully operational in all participating countries by April 10.

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Start your day informed with Metro's News Updates newsletter or get Breaking News alerts the moment it happens.Wizz Air UK boss Yvonne Moynihan said passengers needed to be prepared for delays leaving European airports (Picture: Reuters)But some countries have experienced teething problems with the technology needed to process passengers,leading to delays.Greece has suspended its implementation of the EES this summer to alleviate problems at its many holiday hotspots.The EU Commission has insisted that the system was functioning smoothly at most airports and ports.However Ms Moynihan said passengers should be prepared to wait and should allow as much as three hours when taking a flight out of the Schengen area.She told the BBC: ‘Be conscious that there maybe delays and just to ensure you have the proper supplies with you.’She added that it was hoped airports would bring in ‘extra resilience and extra resource’ to cope with increased numbers during the summer.

How does the Entry Exit System work?

Under the EES,passengers may be asked to provide fingerprints and facial biometrics on entry to all 29 countries in the Schengen area. That is,all EU member states except Ireland and Cyprus,in addition to Iceland,Liechtenstein,Norway and Switzerland.For the most part this is done via self-service kiosks in immigration halls.Passengers are required to scan their passport,provide their biometrics and answer questions on their stay.Passengers are required to register at self-service kiosks,such as these pictured at Madrid Barajas Airport (Picture: Reuters)Registration must also be verified at the point of exit,with many travellers reporting long queues in some countries.Airports facing delays due to a large volume of passengers or technological issues have several options.Firstly passengers can be registered manually onto the system at a passport control desk if the self-service machines do not recognise their documents.Airports can also suspend the system in ‘exceptional circumstances’ for up to six hours,reverting to traditional ‘wet stamping’ of passports.Get in touch with our news team by emailing us at .For more stories like this,check our news page.