One thing to try which seemed to clear up some really bad connectivity issues I had was to go onto the router and reserve an ip address. You don't need to set it as static on the pad as well, but also worth a shot.
I was getting little to no data transfer between the hub and the pad though my ipad2 was fine.
I first tried this on my iphone4s which fixed connectivity problems for it 2 years ago, so I now by default do this for any wifi device.
After doing it for the air, it seemed to smooth out a lot of issues.
However, I'm still getting poor throughput when streaming from youtube and terrible performance when using my kingston MobileLite wifi streamer. The ipad2 and 4s phone will happily play a 2gb movie over the wifi, but the ipad air can hardly even load a 3mb .MOV...
Stu.