More than 620 Air Canada flights, many of them international trips, have been canceled as the clock ticked closer Friday to a possible strike by flight attendants, leaving travelers stranded around the world and scrambling during the peak summer travel season.

The airline said in a news release that it has “suspended all operations” for Air Canada and Air Canada Rouge flights as of Saturday, Aug. 16, due to the strike. The release added, however, that Air Canada Express flights will not be affected, as they are “operated by third-party airlines.”