Have you tried restarting the phone? That might allow you to reset the airplane mode issue. Although you shouldn't be able to connect to wifi if actually on airplane mode.
Your PM SIM is definitely able to receive Alerts as long as it connects to the LTE network, so it's got to be some kind of issue with your phone. What kind of phone do you have? Is it WPA capable?
I had the same problem for a number of months with my phone. I eventually figured out that my house had a dead service spot. I would still have 2 or 3 bars of service on my phone, but calls would cut out or drop, and texts would either not send to ...
