A massive computer failure shut down London airspace this Friday, and airline share prices got smacked.
It's not likely to be an issue for a lot of them: Airline stocks have been soaring in recent weeks. Falling oil prices mean cheaper fuel, one of the main costs of running an airline, so the recent collapse of oil prices is a positive thing for them.
Here's how the stocks moved at the close, since about 3.15 p.m GMT, when the news broke.
EASYJET: -2%
INTERNATIONAL AIRLINES GROUP: -2%
RYANAIR: -0.8%
LUFTHANSA: -1.1%
AIR FRANCE: -2.1%
Initial reports suggested that the traffic wouldn't be flowing again until 7 p.m. GMT but plans began taking off from Heathrow once again by 5 p.m. Delays can cost airlines a huge amount of money if they last for a lengthy period, but todays' chaos is likely to be a little less dramatic than the Icelandic volcano that lost them a huge amount of money in 2010.