I just noticed that there doesn't seem to be the airplane mode option. It is possible to turn the wireless off. Is this the same? The description says it will prevent the device from connecting without asking, but I assume it could still be scanning for networks etc. Presumably in a plane the wifi should be disabled altogether (and this would save power).
As an aside, I preferred the airplane icon to the wifi bars with an x over it (which, to my mind, implies that the wireless is active but not connected). But that is just nitpicking.