I've seen both on onetravel and kayak now, where it describes flights as:
"Secret Carrier"
or "Super saver fare"
eg:
Seven months ago, I asked on this site what that meant, as it was new to me. Now I'm used to knowing, and then got asked what a certain secret carrier was.
After a bit of sleuthing, I was able to work out, for example, which flight left Rome for Warsaw at a particular time, and that was fine. However, it involved some googling and looking up schedules.
Is there a site that you could just give it two airports and one of the dep/arr times and have it tell you the airline?
I admit it's not a terribly complex thing to look for, but if such a site existed, it'd save me some time :)