I am flying on Air Canada but with a Luftansa ticket. (Air Canada metal).
Who should I check-in with? When I try Air Canada, it cannot find my booking number as it's from Lufthansa. When I attempt to do it at Lufthansa's site, it returns a message that it is not possible with this airline.. Please refer to the airline directly. My flight is not for another 2 days, so still a bit early for check-in, but I don't think the error messages matter.

What's the deal?