Royal Air Force fighter jets could use up to 50% sustainable fuel in the future, the Defence Secretary announced on Saturday.
Aircraft such as F-35s, Typhoons and Wildcat helicopters could use algae, alcohol and household waste as fuel, according to the Ministry of Defence (MOD).
The MOD's changed aviation fuel standards came into effect in November and aim to slash carbon emissions.
Defence Secretary Ben Wallace said the UK is "leading the way in sustainability" and the changes to the aviation fuel standards are "simple, yet effective steps" that aim to reduce the "environmental footprint" of defence.
"As we strive to meet this Government's Net Zero carbon emissions target by 2050, it is right that we step up to spearhead these positive changes across both military and civilian sectors," he said.
Sustainable fuel sources known as "drop-ins" include hydrogenated fats and oils, wood waste, alcohols, sugars, household waste, biomass and algae.
Aviation currently accounts for nearly two-thirds of fuel used across the Defence sector.
It is estimated that switching 30% of conventional fuel with an alternative source in a jet travelling 1,000 nautical miles could reduce carbon dioxide (CO2) emissions by 18%, according to the MOD.
Lieutenant General Richard Wardlaw, Chief Defence Logistics and Support, said the Defence Strategic Fuels Authority has been "working tirelessly" with industry partners to change the Defence Standard for Aviation Fuel.
He said: "This is a significant change for defence, enabling us to take a key step towards reducing our CO2 footprint, consistent with our wider ambition for achieving NZ50 [Net Zero Carbon Emissions by 2050]."
Lt Gen Wardlaw added that this is the beginning of "a journey to adopt a range of greener policies and new greener technologies".
The measures are part of the MOD's strategy to reduce its contributions to carbon and greenhouse gas emissions.
The department's ongoing Climate Change and Sustainability Review, led by Lieutenant General Richard Nugee, will also reflect these measures.
The review will focus on a range of initiatives from the department's NZ50 strategy, with findings set to be published early next year.
Cover image: Typhoon jets are among the aircraft that could use alternative, greener fuels in the future (Picture: MOD).