Tomorrow I'm flying to YYJ via YVR from the US on United connecting to the code share puddle jumper. I won't have a problem securing overhead space on my first flight, but I know my bag won't fit on the plane YVR to YYJ. I'm wondering if I can gate check it? If I do, does AC charge for this?
Is your carry-on legal size?
You'll either be on a Dash-8 (DH3) or Q400 (DH4). Dash-8s offer sky-check, so you just drop off your bag before you board and pick it up after. As long as you can get it through security, you should be fine for sky-check.
Q400 doesn't, and there is limited room on-board for legal carry-ons (they fit sideways). If you're on a Q400, make sure you priority board as otherwise you likely won't find room.
If you're UA*1K, then you're *G with AC, and you wouldn't be charged for the bag even if you checked it (under 50lbs). In any case, 90% chance you're on a Dash-8 on the YVR-YYJ route.