(CNN) Hackers targeted air travel and successfully grounded around 1,400 passengers on Sunday.

The problems for passengers started at Warsaw Chopin airport after the airline says hackers breached its ground computers, which are used to issue flight plans. The grounded airline, LOT Polish Airways, told CNN because of the attack it was unable to create flight plans for outbound flights from its Warsaw hub and as a result outbound flights from Warsaw were not able to depart.

Poland's national flag carrier says it was forced to cancel 20 flights and several others were delayed on Sunday after suffering an attack on its IT system.

Sebastian Mikosz, CEO of the Polish airline LOT, is warning all airlines are vulnerable.

"Of course this is an industry problem, not a LOT problem but an industry problem on a much wider scale, and for sure we have to give it more attention, if it can be given more attention," he told Reuters

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