Turn your phone completely off.
Slide out your keyboard
Hold down POWER and X at the same time till you see the M logo then release the POWER button.
You'll see the Android guy, and an Exclamation point.
Hit the SEARCH button.
Should be good to go!
EDIT - Only do this if your experiencing a boot loop, if your stuck in Airplane mode follow this --->
Boot into Clockwork Mod
Install .zip from SD
Reboot after installation.
Should fix your Airplane mode issue.