If you are using fiber optics, you w ill need a light source, either on or off the model. Since they don't eminate heat, they are great for many model applications that require a pinpoint of light. To radiate light in a dome pattern, the LED's are a better choice. For your plane, you may need a mixture of both. LED's must have a power source, so you will either have to find room for batteries on your model, or bring power up through the landing gear (a better choice, as changing the batteries in the model could be difficult).
If you go to Radio Shack or similar, you will find the LED's. The voltage requirements vary, and you need to pay attention to the polarity or you will damage it. The best plan would be to mock up your light system off the model, test all the components to make sure they work the way you would like, and then install them. LED's can be superglued or epoxied into place, as can fiber optics. Experiement a bit, and have fun while you learn
Kurt