Ahh, I mean to mention, you might find this useful (right click, save as... make sure the extension is set to .ulp. If it tries to save it as a .txt file, just save it and change the extension once it has downloaded)
http://ftp.bricsworld.com/EAGLE-FILES/ulp/zoom-unrouted.ulp
If you save it to the desktop or wherever (you can copy it into the 'ulp' folder in the eagle program folder, that makes it easier to use).
Then, when you think you are finished, click the ULP button and navigate to the folder you saved the file and select that. If you saved it in the eagle directory I mentioned, you can just type "run zoom-unrouted" (without the quote marks) in the bar at the top of the pcb editor and press enter.
Basically it zooms right in on the first air wire it finds, then once you have corrected it, you run the ulp again to find the next and so on until it says 'finished' at the bottom of the screen at which point there are no more.
If it zooms right in to a spot on the power or ground plane but you can't see an air wire there, it means that bit of the plane is isolated from the rest (there is a tiny air wire, but you can't make it out).