I have a tethered jailbreak on my iPhone 4 and i am going on a plane for Thanksgiving... would i be ok with just putting it into Airplane mode or do i need to shut it off completely and bring my laptop with me to start it up again? and do i just need any computer that has redsn0w to reboot it or does it have to be mine?
yeah, any computer with redsnow will reboot the phone, but putting it in airplane mode works too. Some planes have wifi, and you can still use your phone on wifi.
They'll say over the intercom to completely power down all mobile devices during takeoff and landing, but as E_Brown said, you don't need to. Airplane mode does the trick.
As the others have said, redsnow I. Any computer will work, BUT some computers won't have drivers installed for an apple device in dfu/recovery mode... So just to be safe make sure iTunes is also installed