Mostly, "Airplane mode" means to disconnect any radio ("wireless") connections, AND stop sending any active probes to find possible connections.
On most Linux systems, Wi-Fi network connections are managed through NetworkManager. Other wireless network connection managers are available.
Additionally, there is a concept called RFKILL. RFKILL means to cut off a certain radio transmitter. In some cases, higher layers such as a Wi-Fi driver might be aware of RFKILL, and return the specific error code
ERFKILL, "Operation not possible due to RF-kill". For example the command
iw dev wlp2s0 scan might return this error.
Airplane Mode in Gnome Shell, or other GUI systems, will activate RFKILL if the hardware supports it. However, your GUI might let you enable Airplane mode even if you do not have RFKILL controls for all your radios... Partly because the GUI cannot reliably tell the association between RFKILL controls and radio devices :-).
In Gnome Shell, the Airplane mode button on the keyboard is just a keyboard shortcut to toggle Airplane mode. When Airplane mode is enabled, I can also see a button in the corner menu which allows to turn it back off.
Some other GUIs use
nm-applet to provide their GUI for NetworkManager. I think
nm-applet had some way to disable Wi-Fi, but beyond that I am not sure exactly what features it provides.
Additionally, RFKILL might be a physical switch which the Operating System can only read, i.e. the hardware/firmware might not allow it to be overridden. This is called "hard rfkill". When the Operating System has control, it is called "soft rfkill".
As the link above explains, you can use the
rfkill list, or simply
rfkill, will let you see if a hard rfkill is active, and what the device name is.
You can also look in
/sys/class/rfkill/. If you know how to inspect
/sys/, you can find the name of the driver which exposes a given RFKILL control. E.g.
$ cd /sys/class/rfkill
rfkill1 rfkill2 rfkill3 rfkill8
$ grep -H . */name
$ ls -l
lrwxrwxrwx. 1 root root 0 Apr 6 10:03 rfkill1 -> ../../devices/platform/dell-laptop/rfkill/rfkill1
lrwxrwxrwx. 1 root root 0 Apr 6 10:03 rfkill2 -> ../../devices/platform/dell-laptop/rfkill/rfkill2
lrwxrwxrwx. 1 root root 0 Apr 6 10:03 rfkill3 -> ../../devices/pci0000:00/0000:00:1c.3/0000:02:00.0/ieee80211/phy0/rfkill3
lrwxrwxrwx. 1 root root 0 Apr 6 15:53 rfkill8 -> ../../devices/pci0000:00/0000:00:1d.0/usb1/1-1/1-1.3/1-1.3:1.0/bluetooth/hci0/rfkill8
$ readlink rfkill8
$ cd rfkill8
$ readlink device
$ cd device
$ readlink driver
$ cd device
$ readlink driver
$ cd driver
$ readlink module
Gnome one of the most integrated Linux GUI systems, and it includes support for Bluetooth. I can see that Airplane mode on my Gnome system activates RFKILL for Bluetooth. Optimistically, I guess that even if the Bluetooth device has no RFKILL control, Gnome's Airplane mode will stop any Bluetooth connections. (And also, stop sending any active probes to find possible Bluetooth connections). My system has a distinct process called
bluetoothd, which I assume has some responsibility for managing Bluetooth devices. However this is all a bit mysterious to me.
Problem with "Airplane mode"
Historically, the most common problem with Airplane mode, or similar features, is that you accidentally activated it when you did not mean to, e.g. by pressing a keyboard button. Then your Wi-Fi does not work, and you might not know why or how to fix it. However, my current Gnome shell is pretty good about soft rfkill. If Airplane mode is enabled, the Wi-Fi menu shows "Wi-Fi off". Clicking on "select a network" in the Wi-Fi menu shows a big notice that Airplane mode is enabled, and gives you a button to immediately disable Airplane mode.