The 3DS does not have a software "flight/airplane mode." You can turn off wireless functions using the switch on the right side of the system.
the walkman mode is the flight mode
on the 3ds sleep mode activates when you close the 3ds while in this mode the power light pulses slowly this means that it is now saving power. hope this helped.
Yes, you can. You can also turn off wireless if needed.
If you just close the lid it should turn the screen off with out turning the console off :)
You buy ds or 3ds games and then put them in your 3ds.
yes just turn it off or put it in flight mode
Go to settings then on personal and change it to flight mode or normal...
push power button once and select "offline" at the bottom of the screen
Yes. One specifically is used to tell the 3DS that the console has been closed and to go into sleep mode.
Unless you have a Japanese 3DS, you can't.
No.
no you dont need to put password to activate your 3DS in the beginning, you put your own code in the first time you turn on and use you 3DS.