I believe Qatar currently codeshares with All Nippon, Asiana, Gol, Malaysian, Middle East Airlines, Philippine Airlines, SNCF, US Airways. Someone feel free to correct me if I'm wrong.
TORONTO/August 8, 2012 – Porter Airlines is implementing its first interline partnership with Qatar Airways. The deal is effective immediately, providing expanded travel options for customers of both carriers.
Qatar’s Doha service to Montreal and Washington-Dulles are both available for Porter interline flights. Montreal connections are available three times weekly to Billy Bishop Toronto City Airport and Halifax. Washington service is available daily to Toronto City Airport.
[Edited 2012-08-08 12:34:31 by srbmod]