WestJet said that more than 200 flights were canceled due to a system outage this past weekend, and more delays and cancellations will be required in the coming days. The outage was also due to a "problem" at the airline's main data center, according to a message to passengers issued Sunday by Diederik Pen, WestJet's executive vice president and chief operating officer. While Pen says the issue has been resolved, his statement also acknowledged that the company's technology systems "still suffer from some instability." Pen's statement said: "Unfortunately, given the scope of yesterday's network impact, we continue to see residual disruptions. More delays and cancellations will be needed in the coming days as we work hard to restore our operations."

Also, in an interview with CTV News on Sunday, Pen detailed the cooling issue, saying the air conditioning system at the company's data center shut down around noon Saturday and could not be restarted, adding: "As a result, the temperature of the entire computer data center rose and shut down. It is the core of our system, and unfortunately, restarting the system took nine hours."

Pen also told CTV News that 144 flights were canceled on Saturday and 100 flights on Sunday, a significant disruption he said would continue to have repercussions through the company's system this week. When asked how many days he thinks it will take for WestJet to return to normal, Pen declined to provide a specific timeframe, saying: "I do not want to make any false promises. We believe it will take tomorrow and perhaps the day after tomorrow for everything to return to normal and stable." He said nearly 6,500 guests affected by the cancellations still need to be rebooked, and the airline is adding flights to its schedule wherever possible to accommodate them.

Additionally, the airline said the outage affected its ability to share information with passengers. Many customers turned to social media to express their frustration, saying they were waiting for hours in check-in lines and lost communication as a result. They also criticized the airline for lack of communication about what was happening, a criticism acknowledged by Pen in his statement and in his interview with CTV News.

On the same note, Pen said, "On behalf of the entire WestJet team, we sincerely apologize to all guests for this unexpected disruption to their travel plans and the resulting impact on communications, which affected our ability to convey information. We deeply regret the unusual events this past weekend that prevented us from providing the experience our guests deserve."

The airline says it is "currently experiencing a very high volume" on phone support channels, email, and social media, and asks guests to check the WestJet app or the company's website for updated information about their flights. Pen said the airline is conducting a "full review" of the incident.