A Lightning to Ethernet adapter allows Wi-Fi calling via Ethernet even when the phone is on airplane mode.

“I could get an adapter on Amazon which was a lightning to ethernet adapter so I can actually plug my fun phone into an ethernet cable yes correct that's I don't think a lot of people realize that I mean if you I think a lot of people are just like shaking their heads now I'm never going to do this but if you wanted to you could plug your phone into a ethernet cable and you don't even need to use your phone you can have your phone completely on airplane mode and still get texts calls because you can do Wi-Fi calling”