Passengers will be contacted from today if their flights are the ones being cancelled by Aer Lingus next week.
Up to 20% of routes will be cut from next Wednesday when pilots begin a work-to-rule.
The members of the Irish Airline Pilots Association are refusing to work overtime or engage in out-of-hours contacts in a row over pay.
Aer Lingus says affected passengers due to travel between June 26th and July 2nd will be notified from today.
They'll be given the option to change their flights, or cancel them and claim a voucher or refund.
