Most airlines allow on line check in these days. The on-line process asks for your citizenship and nationality. Recently, I was able to check in online using my Canadian passport while traveling to Montreal. The airline never specifically asked to see my Canadian passport, they just wanted to see a passport when boarding.
On my trip home I used my US passport of course.
I'll try this again when I travel to Europe in the coming weeks.
On my trip home I used my US passport of course.
I'll try this again when I travel to Europe in the coming weeks.