From http://www.gizmodo.com/gadgets/portable-media/sony/no-psp-on-planes-109594.php:
Here is a story of one guy who was told to put his PSP away on an airplane cause of its supposed interference with the planes computer. Hmmm anyone else have this happen?
lol if wifi took out or messed up planes, terrorists would have a field day. would a bag full of devices that are just regular items that transmit signals, say a cell phone or two, psp with wifi on, laptop, palm pilot, etc, but all things on in a bag and turned on (thats totally legal in every way) mess up a plane to that degree?
no...im HIGHLY sure that anything in the 4.7ghz (wifi) spectrum would mess up any of the planes on board equipment.
Sorry but im a internet tech and i can tell you there is'nt any common wifi that runs on 4.7Ghz. the most common is 802.11B/G and thats 2.4Ghz definatly NOT 4.7.
also 5.7Ghz is common and 900Mhz for getting signal through solid objects.
never used or seen any 4.7Ghz wifi myself but i guess it could exist.
and NO it(psp) wont cause interferance with normal operation of a plane even with wifi on, just follow rules and keep ALL electronics OFF during take off and landing. the ban on using mobile phones on a plane is fedral and i heard they are thinking of lifting that ban so you can use your phone on a plane. ive noticed they tell me i can use my phone right after the plane lands on the tarmac now.