FORT WORTH, Texas & TORONTO--(BUSINESS WIRE)--American Airlines and Porter Airlines are teaming up on a new codeshare partnership to give customers more ways to travel between the United States and Canada. Starting today, customers can book codeshare itineraries on aa.com or American's mobile app, as well as on flyporter.com. "This partnership with American Airlines provides a true competitive alternative for passengers needing more options when flying between Canada and the United States," sai. ...