According to available data, there were several cases of delayed flights. For flight delays or cancellations, Czech Airlines has a form uploaded to its website that allows passengers to contact Czech Airlines for any refund issues.
They also have a dedicated customer service number where the passenger can call with their problems and queries. According Czech Airlines Cancellation Policy air passenger law 261/2004, a passenger can claim up to €600 for flight delays or cancellations. The conditions under which a passenger is eligible to claim compensation are as follows:
The airline the passenger is traveling with must be an EU registered airline
The distance traveled must be at least 1500 Km both nationally and internationally and the delay must be greater than or equal to 3Hrs
And if boarding is denied, which can happen due to overselling tickets.