Transport Minister Marc Garneau closed Canadian skies to the Boeing 7-37 Max 8 aircraft on Wednesday, and that's led to a number of flight cancellations.
Air Canada's customer service line is so swamped with calls it can't even put people on hold, and WestJet says as of yesterday - around a thousand guests were affected, and that number will continue to rise in the days to come.
Tomorrow's WestJet flights to and from Calgary out of the Region of Waterloo International Airport have been cancelled due to the grounding.
In a statement, WestJet says they are working to rebook all guests affected as quickly as possible.
It's not clear how many more local flights will be affected - so make sure to check your flight status before heading to the airport.
With files from the Canadian Press