The head of Europe's airports lobby group says concerns over the region's new digital border control system are keeping him and other industry bosses awake at night.

Earlier this year, the EU completed the roll out of its Entry-Exit System (EES). It requires travellers from outside the EU to register biometric information when entering most European countries, which is then checked when they leave.

Although EES has been working well in some countries, it has also been blamed for causing significant delays at a number of airports, with some passengers missing flights.

Stefan Schulte, president of ACI Europe, said politicians should "stop pretending... that EES is working just fine. It is not."

Schulte, who is also head of the company that owns Frankfurt Airport, told an industry event in Prague: "Passengers are queueing for hours at peak traffic times and I just do not know how we will be able to cope in the coming weeks with the expected increase in traffic."

The BBC has contacted the European Commission, which oversees the EES, for comment.