I have to say, I'm not sure what an aircraft engineer is either. I am a mechanical engineer (by degree) but I work for an aerospace company. I've worked in many jobs at my company. I've been in airplane design that focused on the interiors (sidewalls, stowbins, seats), flight testing where i got to fly on the airplane and test it, and then production support. In Production support, I worked with the aircraft mechanics (the people who actually turn the wrench and build the airplane) to help them fix mistakes and improve design. As the engineer, you dont physically build the airplane, but create the design. We have aircraft mechanics and those are the guys that have their hands on the airplane building. Some of them have A&P (airframe and powerplant) certification, but none of them are engineers. There are smaller company's where you might design and help build the product. A degree in electrical, mechanical, or aerospace would allow you to design airplanes.