When i flew from Amsterdam to Vancouver, in Economy Class with KLM, you could use your laptop (even the internet), phone, camera, ipod, gameboy, psp, etc. no problemo - basically anything, even making phonecalls via a special phone on board which everyone had in their seat and which worked with a credit card. To cut things short, you can use the N900 on a plane without doubt, but just to be sure, turn off GSM (turn on "offline mode").