[JoeD]

The use of phones in airplane mode seems to vary from airline to airline. Last time I flew we were told to turn mobiles off for the duration of the flight, but that any device (including mobiles) that have an "airplane mode" could be used outside of take-off/landing.

I've also been on flights in previous years where even with airplane mode mobiles had to remain off.

I'm sure a lot of people do just put their devices to sleep rather than powering off, probably just out of ignorance that sleep is not the same as off. However, that's still in most cases (phones been a key exception) going to reduce the amount of emissions from a device compared to actively using it.