Lufthansa tech failure leaves planes grounded

More than 200 flights were cancelled at Frankfurt airport after construction work damaged broadband cables caused check-in and boarding problems for German airline Lufthansa.

Thousands of passengers had their flights cancelled or delayed across the world.

The company said engineering works on a railway line mistakenly cut a bundle of cables in Frankfurt on Tuesday.

It has asked customers flying on domestic flights to book train tickets.

The firm said customers could ask for a refund on its website and expects the issues to stabilise by the evening.

More than a hundred flights have also been delayed, according to data from flight tracking website FlightAware.

"Lufthansa asks affected passengers to check the status of their flight on the company's app or website before arriving at the airport. Passengers with domestic flights can switch to Deutsche Bahn until Sunday," the airline said in a statement.

"We regret the inconvenience this will cause our passengers," a spokesperson from the company added.

Air traffic controllers have diverted flights from Germany's busiest airport Frankfurt, but the problem has affected services worldwide.

Lufthansa and Germany's national train operator blamed the fault on a drill which cut through a Deutsche Telekom fibre optic cable bundle.

This meant passenger check-in and boarding systems at Lufthansa seized up on Wednesday and prompted German air traffic control to suspend incoming flights.

However, these have since resumed, with some 40 landings per hour at Frankfurt airport since midday on Wednesday. Germany's DFS air traffic controllers said is nearly normal traffic.

Deutsche Telekom said in a statement: "Two cables have already been repaired overnight by our technical team and many customers are already back online," and said the situation was improving.

Separately, German airport workers are due to go on strike on Friday in a dispute about pay.

Last month, domestic flights were grounded across the US after a contractor deleted files on a crucial computer server used by pilots.

More than 11,000 flights were delayed and at least 1,300 were cancelled on 11 January after the Notice to Air Missions (Notam) system went offline.