I work for WestJet and so far we have access to Air France, Delta, KLM, Cathay Pacific, Allegiant, Condor, Dragonair, Emirates, Era Aviation, Estonian, First Air, Hawaiian, JetBlue, and Virigin America.

I know there are more Airlines joining soon as well.

It is a great system. It is easy to use, and lets you do everything (book, change and cancel). This really opens up the possibilities when travelling standby.