If you are flying with WestJet out of Vancouver, some of their staff are familiar with Airsoft. what they need you to do is declare it, and they will have you fill out and sign a FireArms Declaration Document, state on it that it is:
Airsoft (6mm Paintball)
Ensure you do have it in a case that is lockable and locked (either gun case, or if your suitcase is large enough to hold the original case lock it). Also your battery and BB's should be in a second piece of luggage (checked).
They will then have you take it to the special baggage section, where a security officer will preinspect it to make sure it cannot fire real bullets. Make sure you explain to him before opening the box what it is.
I've travelled several times with my Airsoft guns in my luggage, as long as you follow the rules its all okay.
If you want to make sure you do not have any issues though, as it has already been stated ship it on the bus before you go back home. Although Will at Specarms in Vancouver, has pretty fair shipping rates.
If your knowledge on airsoft and the legalities of it are minor or partial, I'd ship it. Because if you catch a security guard on their off day and they panic, they can call the RCMP, which could result in you missing your flight. Nice thing is some of the RCMP who cover the airport are Airsofters. But dont count on it to work for you if your unsure in any way.
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