Instructions
Look at the size of the aircraft. Some aircraft manufactures make only small or large aircraft. For instance, a small commuter plane will not be made by Airbus, just as Bombardier, a maker of small business jets will not be the manufacturer of a jumbo jet.
Look at the width of the fuselage. A wide-body jumbo jet is most likely made by Boeing or Airbus. Wide body jets have two passenger aisles.
Check the shape of the fuselage. For instance, an Airbus A380 has a very straight fuselage, while a Boeing 747 has a fuselage that is wider and more bulbous toward the front of the plane.
Observe the number of engines. Count the number of engines and observe their locations. Also note if the engines use propellers or pure jet propulsion. Keep in mind that some jet engines also use propellers.
Note the wing shape and location. Faster aircraft will usually have swept back wings. Different airplanes might have wings mounted at the top or the bottom of the fuselage.
Look at the landing gear. Most large planes have retractable landing gear, so they won't be visible in flight. But some smaller planes may have very distinct landing gear configurations, including taildraggers with main landing gear under the wings and a smaller wheel under the tail or pontoons used for aquatic landings.