wifi connectivity when using airplay with appletv

just showing a blank screen.

That could possibly be a HDCP copy protection issue. Is the connection fully HDMI from Apple TV to the screen/projector? Is all the electronics in the chain HDCP compliant?

All iTunes Store video content requires HDCP. However, your own home video does not, and mirroring your desktop would also not require that. But select videos in a browser may require HDCP.

I loose my ability to use wifi as soon as I go into airplay so I cannot show the students things on the web.

Others can do that, so this seems fixable. This is not a documented restriction.

I cannot play a DVD using airplay.

The Apple DVD Player application doesn’t support AirPlay, and probably any DVD Player application that honors DVD copy protection won’t do so. This has always been so.

I cannot use my itune/appletv account to play videos over airplay. I do not want to log the Apple TV itself into my account because it is the schools apple TV.

Make sure that the Apple TV doesn’t switch to cloud versions of that content, as that will only work for matching accounts.

Settings﹥AirPlay﹥Play Purchases from iCloud﹥Off