Differences between classes of seats on an airplane

First Class

First Class is the highest class of service on every flight, this is a class higher than business class.

This class of seat is not available on all airlines, and even if it is available, it is not available on all flights, depending on the flight schedule. It is usually sold mainly on long-haul and transcontinental flights.

Business class

Business Class is an airline ticket class with many special amenities on the plane, this is a ticket class with a higher price than economy class. Most airlines have Business Class seats and they are usually available on long-haul flights. For short-haul flights, with different flight schedules, there may or may not be Business Class.

Premium Economy Class

Premium Economy Class is an intermediate class between Business Class and Economy Class. Airlines decide whether to add Premium Economy Class on each flight.

Economy Class

Economy Class is the most common type of airline ticket and is available on most commercial flights. This is the most common type of seat on each flight.

Each different seat class will correspond to a different quality of service, which is proportional to the airfare of each type of seat. And even within the same seat class/service class, there can be differences in quality, accompanied by different conditions and prices.