Trends since 2000

Together, the ranked airlines went from 38.9 passenger-miles per gallon in 2000 to 67.5 in 2025, a change of 74%.

Efficiency of the whole industry

All ranked airlines combined: total passenger-miles divided by total gallons.

The six largest airlines

Largest six by seat-miles in 2025. Airlines with regional partners include them. Merged airlines start a new line in the year BTS combined their filings.

Total CO2

Efficiency per passenger-mile has improved, but the total depends on how much flying there is. Emissions from these airlines peaked in 2000 at 171.4 million tonnes and were 163.8 million tonnes in 2025.

CO2 from jet fuel burned in scheduled passenger service, at 9.75 kg per gallon.

Year by year

Year	Passenger-miles per gallon	kg CO2 per passenger-mile	Passengers (millions)	Fuel (billion gallons)	CO2 (million tonnes)
2025	67.5	0.144	975	16.80	163.8
2024	67.7	0.144	986	16.67	162.5
2023	66.8	0.146	948	16.14	157.4
2022	67.1	0.145	858	14.11	137.6
2021	62.0	0.157	670	11.09	108.1
2020	49.4	0.197	374	7.68	74.9
2019	66.3	0.147	933	15.90	155.0
2018	65.1	0.150	896	15.53	151.4
2017	64.1	0.152	857	15.02	146.4
2016	62.6	0.156	831	14.88	145.0
2015	61.5	0.159	806	14.62	142.6
2014	60.4	0.161	771	14.20	138.5
2013	59.8	0.163	752	13.96	136.1
2012	58.8	0.166	746	13.90	135.5
2011	56.3	0.173	742	14.35	139.9
2010	55.3	0.176	731	14.33	139.8
2009	53.1	0.183	715	14.36	140.0
2008	51.0	0.191	754	15.77	153.7
2007	49.5	0.197	782	16.60	161.8
2006	48.0	0.203	756	16.47	160.5
2005	46.4	0.210	750	16.60	161.9
2004	44.2	0.220	715	16.40	159.9
2003	42.9	0.227	659	15.14	147.6
2002	41.4	0.235	629	15.31	149.2
2001	38.6	0.253	640	16.66	162.4
2000	38.9	0.251	687	17.58	171.4