My last (proper) girlfriend's father is an avionics tech.
His company don't bother with freight, as they've worked out its much easier to buy him a seat on the next available flight to wherever the AOG is, and he takes his little tool kit and the required parts as luggage.
Quite often we'd go over for a bbq at her folks place on the weekend or something... "Oh yeah sorry, your dad is in the Maldives swapping the radar nacelle in an Embraer E190. He'll be back in the morning."