From the home screen, tap Settings. Note: Airplane Mode disables the wireless features of your iPhone or iPad to comply with airline regulations.
Tap the Airplane Mode slider to turn it on or off. Note: Airplane Mode can also be accessed from the Control Center by swiping up from the bottom of the screen, and then tapping the Airplane mode icon.
When airplane mode is on, the Airplane icon will be displayed in the Status bar. Note: Learn more from Apple support article: Use Airplane Mode on your iPhone.