Musotuner wrote:
Thanks for your reply. The iPad Air is connected to my laptop via a USB cable and the icon is not appearing at the top of the iTunes screen as it always did with the old iPad when it was connected that way. The device manager on the laptop can’t see the iPad either and I have had no messages saying “do you trust this device”, either on the laptop or the iPad. So I’m stuck!
Assuming you don't have any of the other Apple apps installed, try Turingtest's user tip linked in his reply.
If you do have any of the Apple Apps installed, then you either need to download the Devices App, or remove the other apps to return iTunes to its previous functional state.