"Flight mode," at least in Windows 7, is a function of your specific computer, which you have not identified.
Virtually all laptops have a method of turning off the wireless adapter, which is all that "airplane mode" does. This is either a physical switch someplace on the laptop or -- more likely -- pressing the Fn key together with one of the F keys. You'll have to consult your User Manual for the specific key unless you can decipher the icons that are on the F keys.
If you can't figure out the key combination to turn off the wifi adapter, right-click the network icon in the System Notification area and select "Open Network and Sharing Center." Click the link for your wireless network connection and then click the "Disable" button.
EDIT
Because I don't have a laptop with Windows 7, I was unaware of the Windows Mobility Center method shown here --> http://www.youtube.com/watch?v=Ru1VNVZZBkI