I'm American and travel back and fourth between boarders several times a week. If I were to personally transport airsoft anything across the boarder into Canada, it would be seized and my car would be torn apart. It doesn't matter if I own it personally, etc. etc.
I'm not even Canadian and it's my property
Doesn't matter - when you're in Canada...it's their property ;-)
In country transportation of airsoft on aircraft is generally a different matter.