Press release

Despite investments in more efficient aircraft by U.S. airlines, demand growth continues to outpace fuel efficiency gains

Frontier stands out in fuel efficiency on U.S. domestic flights while industry waits for an aircraft CO2 standard

Despite improvements in overall fuel efficiency, CO2 emissions from U.S. domestic aviation continue to grow rapidly, finds a new study released today by the International Council on Clean Transportation. 

Although the fuel efficiency of U.S. domestic airlines increased by 3% between 2016 and 2018, passenger miles travelled increased 10% and fuel use increased by 7%. To date, the United States has not adopted greenhouse gas standards for aircraft to support its goal of carbon-neutral growth for its carriers beginning next year.  Starting in 2020, U.N. rules will require that new aircraft designs being brought to market meet global CO2 emission standards in order to be operated internationally.

Frontier Airlines was the most fuel-efficient U.S. domestic airline in 2017 and 2018, up from second place in 2016. Due to investments in new aircraft like the A320neo, the airline improved the fuel efficiency of its fleet by almost 4% from 2017 and 2018. Frontier also flew more direct routes, and with more passengers per flight, than almost all of its peers. The second and third placed airlines, Spirit and Southwest, burned 7% more fuel on comparable flights.  Worst performing JetBlue burned 26% more fuel than Frontier on comparable flights in 2018.

“Our research shows that investments in new, more fuel-efficient aircraft pay off,” said Sola Zheng, an author of the study.  “It will be interesting to see if other carriers follow Frontier’s lead in upgrading their fleets to reduce fuel burn and greenhouse gas emissions.”

The analysis shows consistent increases in aviation CO2 emissions despite voluntary efforts to increase fuel efficiency. Since 2014, passenger miles traveled have increased three times as fast as the fuel efficiency of airlines are improving.  Domestic airlines in the United States burned 12.5 billion gallons of fuel in 2018, a 17% increase since 2009. With the increase in passenger demand and miles flown, jet fuel emissions per capita in the United States are about 8 times that of the global average.

“It’s surprising that the United States still hasn’t adopted a CO2 standard for new aircraft given how quickly emissions from domestic flights are increasing,” said Dan Rutherford, a study co-author. “The FAA won’t be able to certify new aircraft designs from U.S. manufacturers for international sale starting next year.”

Publication details:

U.S. domestic airline fuel-efficiency ranking 2017-2018

Authors: Xinyi Sola Zheng, Brandon Graver, and Dan Rutherford


Contact:  Sola Zheng, +1 415.818.0206 ext. 1145,

Tracking progress