Well this is a change.
Effective Nov 27th, 2017 – small blades (measuring 6cm or less) will be permitted in carry-on luggage on domestic and international flights – but not for flights to the U.S.
From the Transport Canada press release:
Consistent with international practice, Transport Canada will also amend the list so that very small knife blades (6 cm or less—about the size of a large paper clip) will not be prohibited on domestic or international flights. To respect our security screening agreement with the United States, knife blades of any length will remain prohibited on flights to the United States through preclearance facilities. Razor blades and box cutters of any size will remain prohibited at all screening checkpoints.
So maybe this will mean that if you have a small Swiss Army-type knife on your key chain, you won’t have to have that ‘doh’ moment as you’re waiting in the security line.
Um – can I just bring my water bottle with me?