Southwest Airlines has announced that they plan to refit their 372 737-700s with a new interior. Dubbed “Evolve,” the new interior is a modification of Boeing’s new Sky Interior, which includes large overhead bins, mood lighting, scooped-out window openings and more. Southwest will begin retrofitting their fleet in March, and they hope to finish their 737-700s by the end of 2013.

As part of the new interior, Southwest change their choice of seats. The new seats are thinner and weigh less, yet they supposedly don’t make the seats more uncomfortable. The new seats are made using E-Leather, an environmentally friendly, lightweight, and dirt resistant alternative to traditional leather. E-Leather is made from natural leather fiber that is upgraded and combined with a high performance core utilizing eco-friendly technology. The new seats are considerably cheaper than the old seats that Southwest has, saving them a lot of cost for refits and configuring new aircraft.

The fact that the seats are thinner gives Southwest the space to add an extra row of seats. This raises the capacity of their 737-700s from 137 to 143 seats, an increase of almost 5%. This increase in capacity should improve profitability for Southwest, while hopefully not compromising passenger comfort.