Oomis,
Please don’t call yourself ignorant. You are well informed about more important things (and, more importantly, a real “mentch”, if I may use that term for a lady. Other posters (myself included) have much to learn from your respectful and pleasant manner).
Anyhow, airplane mode (it may be called something else on some models) shuts off all active connections, including the phone, data, wi-fi, and all messaging. Aside from davening, it is useful in situations where you can’t use the phone for these things, and conserves battery.
I agree that it might be problematic even if not halachically so; I personally don’t do it. But since it’s certainly not assur, there are situations where it might be appropriate. And it’s really more a question of what people are used to, so it might not be appropriate in some places, but perfectly fine in others.