When traveling on an airplane, you have to shut off the wireless connection on all of your mobile devices to prevent their radio transmissions from interfering with the airplanes hardware instruments. Offline mode, also called airplane mode, on the Galaxy Tab can be activated or deactivated in the device's Wireless and Network Settings. When activated, Offline mode blocks you from being able to make or receive calls or connect to the internet.
This tutorial will show you how to turn it on.
On the home screen, tap Menu > Settings > Wireless & Networking > Offline profile.
The check mark will turn green, and a small plane icon will appear in the notification panel.
To disable Offline mode, repeat the above steps and remove the check mark — it should change the color of the check mark to gray.