Without price discrimination, there is one price, and then there are two triangles "left" of the price: What consumers would have paid, but don't need to, that's the consumer surplus (between price and demand), and what producers would have sold for, but got more for, that's the producer surplus (between price and supply).

With price discrimination, what happens is that the producers "grab" some of that consumer surplus for themselves (as "price" is not a horizontal line anymore, but gets closer to the demand line).

So this is bad for consumers, good for producers. However, the producers can use the surplus to subsidize products for poorer consumers, so that a higher quantity of goods is sold.

Having said that, the airline market is very weird (oligopoly character, very perishable goods, ...)