This is a well-known fact. A friend of mine MR's from Seattle and he just drives up to YVR to save thousands.

YVR-CTU in UA-P is in the low $2k range.. always. Just be careful with two things:

1. Make sure you can actually book it at that price. UAbomb may reprice based on your location. Maybe a Canadian OTA might price it in CAD and you get a great rate as the USD stays where it's at.

2. Know your mileage accruals. Intra Canada flights, or AC, etc. earn variable rates.