Welcome to the crazy world!
Every one of us (Who has travelled in a plane) has been told to put our phone in Airplane Mode while flying. But why? Maybe it could disrupt the aircraft's communication with air traffic control (ATC) and results in the plane crash.
No, it's just an urban myth. So what really happens when you don't put your mobile on Airplane Mode? Okay, let me tell you.
Airplane Mode disables all the communications protocols on your iPhone, Android or whatever phone you're using. It disables Cellular communication along with WiFi, GPS, and Bluetooth.
When Airplane Mode is enabled, you'll often see an icon on the notification bar showing an aeroplane.
So you could enable WiFi even on Airplane Mode.
It's also helpful at ground when you're low on battery.