How can airplane mode interfere with WiFi? I am in a hostel for the second night.  WiFi worked great yesterday.  Today, it asks for the password instead of remembering, but doesn't accept it.  Keeps asking.  I have airplane mode on to prevent cell usage but WiFi and Bluetooth on.  

So I turned off airplane mode and the WiFi immediately connected without asking for password.  (However, it later disappeared.)
Airplane mode turns WiFi off

From the Apple Support article


  When Airplane Mode is on, you'll see [an airplane icon] in the status bar of your screen or on your watch face. In Airplane Mode, these wireless features are turned off: Cellular (voice and data) Wi-Fi Bluetooth