Hi I'm Ben. How are you?
I don't know how often they fly to Vancouver, I didn't even know they did. Go to the Aeroflot's website, you'll know more than I do about this airline.
I don't know if they fly direct to the West Coast from Moscow, but if they do they would operate a 777-200IGW on those flights, not an IL-62. I think it's the aircraft that has the longest range in Aeroflot's fleet. They have 777 don't they? I know they don't have any 747-400's (in fact they have never had any 747 at all). The IL-62 wouldn't fly Seattle/Vancouver-Moscow nonstop would it? So if you saw an IL-62 in Vancouver if must have stopped somewhere for refuelling, maybe Reykjavik, Gander,...I don't know. Or maybe it went the other way around through the 180° meridian and then landed in Anchorage for the same purpose.
Oh by the way, have you ever been on Aeroflot? I have never traveled with them but I heard the service on board is not too good.