United is buying 40 new 737-700s to upgrade its aging fleet

United Airlines

United Air Lines has announced the purchase of 40 new Boeing 737-700 airplanes to replace some of the smaller, older planes operated by its regional carriers. The company has not revealed how much it spent to acquire the new aircraft.

The new planes will enter its fleet in mid-2017.

United’s current 737-700 aircraft seat 118 passengers, with 12 first class seats and 40 Economy Plus seats. The company hopes to replace more than half of the 50-seaters in its fleet by 2019.

“Our customers have a preference for an improved travel experience, including first class seats, Economy Plus, and Wi-Fi. These aircraft are an efficient way to meet those needs,” said Gerry Laderman, United’s acting chief financial officer.

News of the purchase arrives just days after United reported $934 million in profit for Q4 while failing to hit earnings and revenue projections. The company’s profit was earned mostly through plummeting gas prices which significantly pushed down operational costs. United saved nearly $4.2 billion on jet fuel costs in 2015.

Shares of United have fallen more than 20% so far this year, follow a nearly 15% decline in 2015.