Porter Airlines says problems that created long lines at Billy Bishop Airport Wednesday and frustrated passengers have been resolved.
Porter blamed a telecom outage in the United States for an outage that meant the airline couldn't check passengers in, validate their passports, or allow them to change flights.
Issues Wednesday night cancelled 20 flights.
Thursday morning Porter said passengers would be rebooked as soon as possible with flight information sent by email.
Passengers forced to cancel travel because of the technical issue are eligible for full refunds to be processed later.