personally I don't want people to be able to use their cell phones on a flight.
Flying is stressful/annoying/uncomfortable enough in coach without 250-300 annoying ass people b*(^)%$g about significant others,family members, the shoes they bought, etc.
Can you imagine the general noise level that would build while you're trying to relax on a 6-12 hour flight? Especially when you get the moron right next to you talking on theirs.
Ugh, I don't even like to think about it.
Personally though, I don't see whats so crazy about just advising to use airplane mode the same way you advise to turn phones off. It's no more difficult for the user and they trust people to turn them off, so what's the change for a different button to hit?