The ordering process for factory-new aircraft.
The ordering process for used / second-hand aircraft.
How to sell or lease your airplane to other players or to the AI brokers.
How to change the seating configuration of your aircraft.
How to choose your aircraft fleet to maximize the operational and economic benefits.
How to convert your aircraft, for example, into a freighter.
How to upgrade your aircraft with hushkits or winglets.
How to put your aircraft to long-term storage if you are not using it just now.
How to sell your aircraft to the junkyard and retire it.
Some background information about the realistic performance model of the aircraft and routes.