Here's a look at how various airlines are changing the seats on their planes.
Alaska Airlines is adding an extra row of seats throughout its fleet, which is all Boeing 737s. It's planning to add power outlets at each seat, a rarity among U.S. airlines.
It's adding five seats on its MD-80s in a project due to wrap up in November. American is still considering whether to add an additional row on its Boeing 737s.
DELTA AIR LINES
Delta is putting slimline seats on many of its planes, including its MD-90s, Boeing 737s, 747s and some 757s. Those seats allow Delta to add an extra row on some of those planes.
JetBlue plans to replace the seats on its Airbus A320s — the bulk of its fleet. It hasn't finalized the seat measurements but says it has no plans to add an additional row.
Southwest has added an additional row of seats on most of its fleet. Passengers lost about one inch of legroom, although the airline says that changes to the seat design mean no loss in comfort.
New seats going into United Airlines' Airbus A320s are an inch closer together, but the airline says passengers actually have more than an inch of additional space above the knee. It also says the new seats are slightly wider — but the aisles are an inch narrower. United is also putting new seats on most of its Boeing 737s.
No plans for a big seat overhaul, but it added four additional seats on its Airbus A321s, for a total of 187. It fit them in by putting two new seats on each side of a rear exit row.