If you can't get the wireless to turn on, and airplane mode seems to be stuck in the 'on' mode, check the wireless key (or button or switch) on your machine. I have one that you can't tell if it's on or off, and it was off, which explains why I could not connect (Dell Inspiron N4010).
On the wireless drop-down panel, it said wireless was off and no networks appeared. I turned it on, but it didn't go on.
I opened the wireless network settings and tried to turn it on, but it wouldn't go on. I noticed Airplane Mode was on, so I turned it off. It looked like it went off, but the wifi still wouldn't go on. I closed the window and opened it again, and the airplane mode was back on.
I finally thought to check the wifi button on my laptop. I don't have a light that indicates if the wifi card is enabled/disabled, so I can't tell. I pressed the key, and then the wireless turned on automatically.