It's beyond easy to pair AirPods with a non-Apple device. And on Arch, it's trivial to have the AirPods appear in the bluetooth manager (in this case, blueman-applet)--but when you try to initiate pairing, it does not succeed.

The trick here--if you don't require pairing with Bluetooth LE devices--is to manually specify that the bluetooth controller (bluez) use BR/EDR transport rather than allow both transport modes.

Open a shell and do the following:

$ sudo vi /etc/bluetooth/main.conf

Uncomment and manually set ControllerMode to BR/EDR:

# Restricts all controllers to the specified transport. Default value
# is "dual", i.e. both BR/EDR and LE enabled (when supported by the HW).
# Possible values: "dual", "bredr", "le"
ControllerMode = bredr

Restart the bluetooth service:

$ sudo systemctl restart bluetooth

Try re-pairing!