The mystery of the missing iPad AirPlay button
I took my own iPad out to make sure it was still there. It was. Both iPads were upgraded on the same day to 4.2.1. Both iPads used the same network to stream to the same AppleTV. You may have seen the demo. Yet his iPad doesn’t have the AirPlay button, and mine does.
I tried the Video app, iPod app, YouTube app, Netflix, and Photos. None of the apps had the AirPlay button they once had.
This Apple Support forum thread points to a bug when the language is changed on the device.
Changing language (English > French > English) brought back the AirPlay icon on iPod on my iPhone 3Gs v4.2.1. It came back on the first switch to French, and also when I switched back to English. Prior suggestions of rebooting did not correct the situation.
This seems out of character for Apple, who has a long history of reliable software.
UPDATE with solution
The AirPlay button does not appear on the device while it is connected to 3G. AirPlay requires a WiFi or Bluetooth connection. This iPad didn’t automatically switch to WiFi, so I manually switched it and the button reappeared.
This seems like the the same problem other people have had. Their solutions must have reset their connection to WiFi.