Yes, you can only use the companion ticket on CP operated aircraft. I don't think it's true that CP flights are showing as AC flights yet.
First of all, they haven't set the new summer scheulde yet which the Globe and Mail said Milton will talk about today when they show the public the new aircraft.
One note of caution, I checked ITN for flights between YYZ - LHR and guess what. Out of the usually 3 flights, two of the flights are already showing "FULL" in all classes in May(that's the only month I checked). This is totally impossible which once again imply the "Phantom passenger" theory. So something is defintely going on with those 2 flights. I am just about fed up with CP continuely doing this.
Either cancel it or let us book it, don't lie to us and say it's full.
BTW, have anyone been able to get the usually (14 day or 7 day) advance fare for flights between YYZ - YVR especially in Feb & March? It's usually around $400 for a 14 day advance and now I am getting a quote of around $585. It's defintely not a coincidence. Unless I am having a memory loss this morning, I don't remember paying this high for a 14 day advance fare. So what's all those about fare will stay the same blah blah blah... I am just about fed up about them pulling these tricks making us having uncertainly on the flights that we are booked on. One of these days I am just going to stop travelling with AC/CP and redesign out travel schedules so me and my colleague can take our 100K business elsewhere.
Sorry to be off topic, but it just got me going...