Unfortunately being made of foam it's lifetime was limited and we finally busted the little wires that run through the middle of the prop. Rather than just toss it we had to take it apart to scavange for reusable parts. I knew it had to be a super capacitor in there and indeed it was. 2.7 volt 7 farad. The motor we salavaged for some future project, but the charger and capacitor we kept together and added a multi-chip warm white power LED that I got off ebay a long time ago. I was using these for outdoor lighting long time ago but they didn't really last in that application, or I was overpowering them, so I had a bunch in the toolbox. There is a tiny board in there that shuts off the motor till it leaves the launcher, but we didn't use that, just soldered directly to the capacitor. The voltage is close enough that I didn't bother with a resistor or anything.
The charger is really quite powerful, about 7 seconds of cranking will run the LED at decent flashlight level for about a minute and a half with many more minutes at diminishing candle and then "find me" levels.
And of course you can shoot it across the room too as it's still on the sled that used to launch the airplane.
I haven't played with any of this new generation of super capacitors before, but they are certainly going to be useful! You couldn't use a battery in this kind of thing, it wouldn't work at all. I see now that there are a bunch of different versions of this toy, they aren't expensive and it was definitely fun. I'm not sure how we managed not to lose it into a pond or up on a roof or tree while we had it, and when it does inevitably crash and burn like all toy airplanes must, you can salvage the really cool super cap out of the inside!