WestJet says they are working with police in Calgary and the RCMP cybercrime unit after members' profile data was disclosed online by an unauthorized third party.
The airline says they have taken immediate steps to secure affected systems.
A news release Executive Vice-President and Chief Information Officer Craig Maccubbin was quoted as saying "The privacy and protection of our guests' information is a matter we take very seriously and we have worked swiftly and aggressively to resolve this incident. WestJet is in the process of contacting affected guests and we deeply regret any inconvenience this may cause."
None of the data contained credit card or banking information.