I have an opportunity to fly on Air Canada to London. I have an option on flying on B767, A343, or A333 through Toronto, Calgary, Vancouver, or Montreal. Could anyone please help me with any suggestions on which aircraft type should I fly and what’s the best airport in Canada to spend time out and for spotting? Any comments/suggestions are greatly appreciated. Also is the LHR route on A340 is it a 343 or 345?