On iPhone the airplane toggle is the cellular toggle. It leaves all your other radios active.
It also disables GPS but only because that doesn't work anyway in a fast moving faraday cage without cell tower triangulation.
If you want to disable wifi or bluetooth, those are separate toggles... and by default they just disconnect from your current wifi network and some of your bluetooth devices (your smart watch for example, will stay connected over bluetooth). The buttons are there to use if your wifi or bluetooth aren't working properly, which can always be fixed by just disconnecting rather than disabling the radio entirely.