Thank you for your help.
I have an Apple MacBook Air with the latest operating system, an HDTV, and an Apple TV purchased in NYC last April or May. Can I use airplay to watch on my television films or TV shows downloaded onto my MacBook Air online e.g. from BBC iPlayer Web?
Best wishes - Richard
I think you would need Mirror to do that, I do it that way but I cannot say definately no to other methods, just I don't think so.
For Mirror you need MacBook Air mid-2011 or later with OS X 10.8 (which you say you have). If you Air is earlier check an app called air parrot.
The down side is I get Eastenders in 55' and not 5 on my iPod!