A fuselage is the main body of an airplane, the long tube-shaped section where passengers sit, cargo is stored, and pilots control the aircraft. Think of it as the central structure that everything else attaches to: the wings connect to the fuselage, the tail extends from the back of it, and the engines either hang from the wings or mount on the fuselage itself.

The fuselage has to be incredibly strong to withstand the forces of flight while being as light as possible, so engineers design it using aluminum alloys, composite materials, or other specialized metals.

If you've ever flown on a commercial airliner, you were sitting inside the fuselage, looking out through windows cut into its sides. In smaller planes, the fuselage might barely fit two people sitting side by side. In massive jets like the Airbus A380, the fuselage is wide enough for two aisles, with seats on both sides and in the middle.

Military aircraft, cargo planes, and passenger jets all have fuselages, though they look different depending on their purpose. A fighter jet's fuselage is sleek and narrow for speed, while a cargo plane's fuselage is tall and wide to carry heavy equipment.