American Airlines is planning to cut legroom in its economy cabins by two inches.
The seat pitch on its new B737 Max aircraft will drop from 31 to 29 inches in three rows of economy.
The airline is also considering “something similar” for its 737-800s aircraft.
There are reports this is to make room for additional passenger seats although American have refused to confirm this.
American has ordered a total 100 new B737 Max aircraft, the first of which are due for arrival this autumn and will be used mainly on North American routes.
Legroom across other US carriers such as Delta and United ranges between 30 and 31 inches. JetBlue Airways, Southwest Airlines and Alaska Airlines offer between 31 and 33 inches.
American Airlines spokesperson said: “We are planning to have up to three rows at 29-inch pitch on the 737 Max when it begins arriving this fall. We’re also considering something similar for our 737-800s beginning at a later date. The seats we’ll use on the Max are designed to maximise personal living space while allowing more comfort, even in arrangements like this where the pitch is a little tighter.”