The use of abstraction in OOP refers to the practice of extracting the underlying properties of an object we are modelling and making available those properties that are required for other clients. We use abstraction to generalize something, based on the existing context of the problem. For example, we can abstract an airplane into an Aircraft class, but what properties we include are entirely dependent on the domain.
In a flight simulator, we might enclose aerodynamic properties (roll dates, speed, altitude - stuff pilots care about). In a booking system, we are more concerned with cabin types, seat numbers, etc.