From the BBC
"Up to half of all European flights on Tuesday could suffer from delays due to a failure in one of the systems used to manage air traffic.
Eurocontrol, which co-ordinates flights across the continent, said almost 15,000 scheduled trips "could have some delay".
Contingency plans put in place have reduced the network capacity by another 10%, it said.
The problem is expected to be solved late on Tuesday evening."
And before anyone asks the delays will not be eligible for EU 261 compensation.