My contributions are minor compared to such things as irrops communication and landmark orientation. But among those not yet mentioned:

1) When I was a kid (1970s) and used to fly internationally, transatlantic flights to the US always featured a concluding announcement from the pilot: "...and if you're a U.S. citizen, welcome home." Now I almost never hear this. And I miss it.

2) Why is the entire airline industry seemingly fixated on announcing preparations for landing with the phrase, "we'll be on the ground soon?" Of course it's not the case, but it implies that you're choosing your words carefull so you can't be criticized for excessive optimism if you don't get us on the ground by means of a safe landing. Why can't you just say, "we'll be landing soon?" It wouldn't matter if the "on the ground" phrase weren't so consistent, as if it's some kind of industry law or something.