Unable to get wifi on a flight

I used to have no problem connecting to the free inflight wifi offered on several airlines. But for over a year now, I cannot. I’ve tried powering off then back on, followed all directions given by the airline, but now wonder if my phone is just getting old because it is also happening at several public wifi networks I used to be able to access for example in restaurants. What can I do to restore connectivity with public wifi? It works fine on my home wifi.