Correct something like that

What I heard is;
Skype you can make calls while inflight on the airplane that offers wifi , where as a normal cell phone you cannot . It's that wifi -vs- satellite

My nokia phone would also still lose charge while tethered and plugged in. It's not just the wifi and/or 3G chips being kept hot, the actual constant data transfer up/down when browsing (in particular) takes a lot of juice as it involves constant flash memory activity too for data caching. Oh, and I had mine tethered by bluetooth too, so that was running as well! So you're basically using most of the phone at once in a fairly constant manner. And if the screen doesn't dim, there's that too. etc. etc. As the iphone's running a big OS compared to the nokia, I'm not surprised that there's faster battery drain as there's more constant housekeeping activity going on. It's the price we pay for a skinny phone that's almost a laptop.