Like your smartphone and other mobile devices, Windows 11 has an Airplane mode feature that instantly disables all of the wireless radios in your PC. Depending on the capabilities of your PC, this can include Wi-Fi, Bluetooth, cellular data, and Near Field Communication (NFC).
Despite its name, Airplane mode isn't only useful when you're on an airplane. If you're using a laptop on battery power and don't need connectivity, you can enable Airplane mode to improve its battery life.
Toggle Airplane mode
You can enable Airplane mode via the Settings app (WINKEY + I): when you navigate to Network & internet, you will see an Airplane mode setting. But there's a quicker way: open Quick settings (WINKEY + A) and click the Airplane mode button.

When you do so, the Wi-Fi and Bluetooth quick settings buttons will note that those radios are disabled, and the Network icon in the notification area will change to an airplane-shaped icon.

To disable Airplane mode and re-enable any impacted wireless radios, simply toggle it as you did before, either in Settings or Quick settings.
Configure Airplane mode
Airplane mode may seem simple enough, but it does have one useful additional feature: if you enable Wi-Fi and/or Bluetooth while Airplane mode is enabled, Windows 11 will remember that and leave those radios enabled the next time you engage Airplane mode.
There are many reasons why you might want to enable a wireless radio while in Airplane mode. The most obvious is to use a pair of Bluetooth-based earbuds.
The easiest way to do this is via Quick settings: with Airplane mode enabled, simply toggle on Wi-Fi or Bluetooth.

You can also use the Settings app to determine which wireless radios stay on while in Airplane mode. To do so, open the Settings app and navigate to Network & internet > Airplane mode. Then, enable Airplane mode and configure the wireless radios in the Wireless devices list as you prefer.