The Polish airline LOT was forced to cancel flights after its ground computer systems were hacked

Warsaw: About 1400 passengers of the Polish airline LOT were grounded at Warsaw's Chopin airport on Sunday after hackers attacked the airline ground computer systems used to issue flight plans, the company said.

http://www.smh.com.au/world/hackers-ground-1400-passengers-at-warsaw-airport-20150621-ghtxwe