Most airlines have a different fare class for each letter of the alphabet, and this varies by airline: F is first class, C and J are typically business class, and Y is usually economy, regardless of the airline.
On a passenger jetliner, first class usually refers to a limited number (rarely more than 10) of seats or cabins toward the front of the aircraft which have more space, comfort, service, and privacy.
E and Y are fare classes within the Economy Cabin - the difference will be related to the terms and conditions of the ticket with regards to issues like upgrades and change fees. The inflight service will be exactly the same. Yep, to the pax, just considering the inflight experience - nothing.
The cabins and booking classes that are valid for Iberia are: Business Class (J,C,D,R,I), and Economy Class (Y, B, H); for British Airways: First Class (F, A,), Club World (J, C, D, R, I), World Traveler Plus (W, E,T) and Economy Class (Y,B,H); for American Airlines: First Class (F, A), Business Class (J, D, R, I) and ...
Here are a few fare codes that are typically the same across all airlines: Y: Full-fare economy-class ticket. J: Full-fare business-class ticket. F: Full-fare first-class ticket.
The letter Y generally stands for economy class, while Q is an economy ticket purchased at a discounted rate. If you see a B you might be in luck—it means you could be eligible for a seat upgrade.
There's little doubt that first class offers a great deal more luxury, but it comes with a hefty price tag. While business class may not be as luxurious as first class, it's far nicer than economy, and surprisingly comfortable.
Economy class, also called third class, coach class, steerage, or to distinguish it from the slightly more expensive premium economy class, standard economy class or budget economy class, is the lowest travel class of seating in air travel, rail travel, and sometimes ferry or maritime travel.