The airline companies have%A0classes system in their airplanes with which their customers can get the seat to travel according to their needs. The classes are usually economy which is the lower one and has minimum ticket price, then first class and business class which is the most expensive one.
Each class has its own perks and level of comfort and several other things are also available. The airline companies have made the ticket pricing system accordingly.
All of the details are explained very well in this video which can be very informative for you.