Was searching for hours and programming my DX6i to make the throttle hold work in airplane mode.
Saw a lot of posts about changing the throttle cut switch to a toggle switch.
My way is easier. Just open the back of the radio-6 screws and move the wires from the throttle cut switch to the hold switch on the plugs. It is easy to remove the wires from the plugs by pulling on the wire while moving the small plastic tab that holds the wires in the plug.
Simple and free and takes 5-10 minutes and does not make any soldering necessary.