Check out Micromark and look at their fiber optic starters kit. It's about $20 or so and comes with a battery cradle/switch assembly that leads to the lights. I have one for a model ship I intend to do some time soon (I hope). You would likely need a base and then just run the wires into the aircraft for a small one, for a 1/32 you could easily mount it inside, you'd just need a way to move the switch. With a little ingenuity though, I'm sure you could figure something out.
Groot