U.S. airlines set records for passenger traffic in 2015

The U.S. airline industry, already reaping huge profits from a steep drop in fuel costs, is setting records for passenger traffic.

For all of 2015, the nation’s air carriers broke records for the number of passengers carried (798.4 million), the percentage of filled seats (83.8%) and the total miles traveled with paying customers (902.4 billion), according to data released Thursday by the U.S. Department of Transportation.

The latest numbers show that demand for air travel remains strong but the nation’s carriers continue to be frugal about adding new capacity in the form of new planes and extra flights.

The percentage of filled seats in 2015, also known as the load factor, exceeded the previous record set in 2014 at 83.4%. The high rate means that finding an empty seat on a plane is increasingly rare, as airlines pack cabins as full as possible to generate the highest revenue per flight.

The total number of passengers carried for 2015 eclipsed the previous high of 769.6 million, set in 2007, before the nation’s last financial crisis. The number of miles traveled, multiplied by the number of paying customers, also known as revenue passenger miles, surpasses the previous record of 862.5 billion, set in 2014.

The new records come as most of the nation’s biggest carriers report hefty profits, thanks in part to fuel costs that have dropped by nearly 40% over the past year. A series of mergers in the past decade also has put control of more than 70% of all domestic travel in the hands of four carriers.

For 2015, the 10 largest U.S. carriers reported pre-tax earnings of $23.2 billion, with a profit margin of 14.6%, up from 6% in 2014, according to Airlines for America, the trade group for the nation’s airlines.

Although airline critics have said that the industry should respond to the strong revenue and lower fuel costs by reducing fares, the trade group has noted that carriers have instead invested a big share of the profits in new planes, overhauled terminals and lounges and dividends for shareholders.

In 2015, the airlines took receipt of 388 new planes, with 10 carriers reporting $86 billion in firm orders for new aircraft to be delivered in 2016 and beyond, according to the trade group.

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