Three cabins on most aircraft
Most US aircraft on the routes in this catalog stack three cabins: economy, premium economy, and business or first. The labels change per operator; the underlying product does not.
Economy
The largest cabin and the cheapest. Economy is split into sub-fares (basic, standard, plus, flex). Basic strips out seat selection, carry-on overhead, and same-day changes; flex adds them back at a higher price. The seat itself is usually identical across the four — what changes is the rules around it.
On a transcontinental US flight a typical economy seat has 30-32 inches of pitch and a recline of 3-4 inches. Beverage service and a snack are included on most operators; meal service is included on long-haul routes longer than 6 hours. In-flight entertainment is operator-dependent — some carriers have seatback screens, others stream to your phone or tablet.
Premium economy
A separate cabin between economy and business with extra legroom, a wider seat, free alcohol, and a dedicated meal service. On long-haul transatlantic and transpacific routes the upcharge over standard economy is typically 80-150%, which buys you noticeably better sleep on overnight flights.
The product is at its strongest on overnight flights of 8 hours or more. The recline, footrest, and meal pacing are designed for a long sit, and the lower cabin density (typically 28-35 seats versus 200+ in economy) means quieter ambient noise and shorter boarding and deplaning. It is at its weakest on short hops where the cabin product does not have time to deliver value.
Business and first
The front cabins. On most US transcontinental routes you will see lie-flat seats; on shorter regional routes you will see recliners. The cabin is sold separately and often as a fare-class bundle (e.g. flexible business with no change fees, free baggage, lounge access, and priority security).
On a long-haul international flight a typical business seat is a flat-bed product with direct aisle access, a dedicated cabin, multi-course meal service, and lounge access at both ends. The upcharge over economy is typically 4-6x. On a short-haul domestic flight a "first" seat is usually a wider recliner with a small upcharge over standard economy.
Single-cabin and ULCC operators
Several operators do not stack three cabins. Single-cabin point-to-point operators have one fare class, no assigned seats, and free baggage. Ultra-low-cost carriers (ULCCs) sell the lowest base fare and unbundle every other product — every bag (carry-on included) is paid, every seat is paid, and even drinks are paid extras.
The trade-off is straightforward: single-cabin operators are the right cube for cost-conscious travelers who don't need premium amenities and don't want to pay for bags. ULCCs are the right cube only when the all-in price (after baggage, seat selection, and the punitive airport-side bag fees) still beats the network alternative.