No Airplay icon in menu bar for brand new 2012 macbook Air and AppleTV 2.

All software is up to date on everything. Will airplay through iTunes on the computer, and with Ipad2 just fine but why not with newer MacBook Air? Again, all software is up to date, All models are compatible as I have already checked, but there is not an airplay icon on the menu bar when both devices are connected to the same network. I have seen similar questions posted and they seem to suggest that the devices are not compatible, but this is not the case with me since everything was purchased within the past two months.