The global airline industry transports between 3.5 to 4 billion people annually. Its economic impact is over $2.7 trillion annually. To understand how an Industrial Internet project can be used to improve maintenance planning and scheduling and for future reference in other sections, we will begin with a simple description of the major parts of the aircraft:

• Fuselage: The fuselage or the body of the airplane provides a connection point for all major assemblies. The front of the fuselage is the cockpit where the pilot controls the aircraft while passengers and cargo are carried in the rear. The aircraft fuel in carried in some cases in the fuselage, while others carry fuel in the wings.
• Wings: The wings help to balance and improve the aircraft's stability when flying. The wings generate thrust to allow the aircraft to take off and climb to the cruise altitude. There are two wings that are joined by a fuselage. The shape of the wings is designed and optimized for thrust and fuel efficiency.
• Engines: The engines are critical parts of the aircraft that enable its movement on the runway and generate the thrust for the flight. The diverse types of aircraft require engines that are made in accordance to the aircraft size and weight. There are different types of jet engines, but the two types that are widely used are turbofan and turbojet. Generally, commercial aircraft have two or four engines.
• Landing gear: Landing gear is the undercarriage of the aircraft that is used for either takeoff or landing. The landing gear supports the aircraft when it is not flying, allowing it to take off, land, and taxi on the runway, safely.
• Avionics: Avionics are the electronic systems of the aircraft. It consists of the navigation system, the display and management of multiple systems, and the communications systems. It may include some early warning and control systems as well.

The following diagram illustrates the structure of a simple aircraft:

The components and their suppliers for present day commercial aircraft are very complex, consisting of many parts and subsystems. This complexity is apparent during commercial operations and aircraft maintenance on the part of airlines. The following diagram illustrates the structure and major suppliers for the Boeing 787 (https://www.researchgate.net/figure/268209377_fig4_Figure-4-Vehicle-Level-Health-Reasoner-Overview-Diagram-with-information-exchange-data):

Airlines are in the core business of flying passengers and their baggage or cargo from one place to another. They continuously make complex decisions on how to maintain the fleet of aircraft in a good condition. Airlines such as Delta and Lufthansa are known to have their own MRO operations, while many other airlines rely on manufacturers and other parties.

The airlines that operate commercial services are overall responsible for MRO activities, including the inspection or modification of an aircraft or aircraft subsystems and components. These maintenance activities can include such tasks as ensuring compliance with Airworthiness Directives or Service Bulletins.