# Top 26 Sustainable Aviation Startups Worldwide by Funding (2026)

> The 26 best-funded sustainable aviation startups worldwide, ranked by total funding raised: $491M combined.

Source: https://millionrounds.com/top-lists/sustainable-aviation-startups (Millionrounds; every figure on the page links to its filing or article)

- 1 [**Heart Aerospace** Heart Aerospace is a manufacturer of hybrid-electric regional aircraft, focused on creating sustainable air travel solutions.](https://millionrounds.com/company/heart-aerospace) Heart Aerospace is a manufacturer of hybrid-electric regional aircraft, focused on creating sustainable air travel solutions. *Founded* 2019 Torrance, Sweden **$107M** last round Feb 2024
- 2 [**Reaction Engines** Reaction Engines is a British aerospace and engineering company founded in 1989, based in Culham, Oxfordshire.](https://millionrounds.com/company/reaction-engines) Reaction Engines is a British aerospace and engineering company founded in 1989, based in Culham, Oxfordshire. *Founded* 1989 Abingdon, United Kingdom **$93M** last round May 2023
- 3 [**LanzaJet** LanzaJet is a private company founded in 2020 that focuses on sustainable fuels technology.](https://millionrounds.com/company/lanzajet) LanzaJet is a private company founded in 2020 that focuses on sustainable fuels technology. *Founded* 2020 Chicago, United States **$67M** last round Oct 2026
- 4 [**XFuel** XFuel produces sustainable and net-zero road, marine and aviation drop-in fuels](https://millionrounds.com/company/xfuel) XFuel produces sustainable and net-zero road, marine and aviation drop-in fuels *Founded* - Dublin, Spain **$41M** last round May 2026
- 5 [**Lunar Outpost** Lunar Outpost is a private aerospace company based in Golden, Colorado, focused on building robotic infrastructure to support a sustainable human presence on th](https://millionrounds.com/company/lunar-outpost) Lunar Outpost is a private aerospace company based in Golden, Colorado, focused on building robotic infrastructure to support a sustainable human presence on th *Founded* 2017 Golden, United States **$30M** last round May 2026
- 6 [**STELLARIA** Stellaria is an Emirati tech company founded in 2021 and based in Abu Dhabi.](https://millionrounds.com/company/stellaria) Stellaria is an Emirati tech company founded in 2021 and based in Abu Dhabi. *Founded* 2023 Abu Dhabi, France **$27M** last round Jul 2025
- 7 [**Karman+** We want to mine space resources from near-Earth asteroids to provide abundant, sustainable energy and resources in space and for Earth.](https://millionrounds.com/company/karman) We want to mine space resources from near-Earth asteroids to provide abundant, sustainable energy and resources in space and for Earth. *Founded* 2022 Denver, United States **$20M** last round Feb 2025
- 8 [**Vaya Space** Vaya Space is a sustainable aviation and aerospace company producing rockets for low-reach orbit.](https://millionrounds.com/company/vaya-space) Vaya Space is a sustainable aviation and aerospace company producing rockets for low-reach orbit. *Founded* 2017 Cocoa, United States **$17M** last round Jan 2023
- 9 [**Unum Aircraft Seating** Unum Aircraft Seating is a UK-based aerospace startup that designs, develops, and manufactures lightweight and sustainable business-class airline seats.](https://millionrounds.com/company/unum-aircraft-seating) Unum Aircraft Seating is a UK-based aerospace startup that designs, develops, and manufactures lightweight and sustainable business-class airline seats. *Founded* 2020 Crawley, United Kingdom **$16M** last round Apr 2026
- 10 [**Circularity Fuels** Circularity Fuels converts biogas into sustainable aviation fuel.](https://millionrounds.com/company/circularity-fuels) Circularity Fuels converts biogas into sustainable aviation fuel. *Founded* - Palo Alto, United States **$15M** last round Nov 2026
- 11 [**InspeCity** InspeCity, also known as InspeCity Space Laboratories Pvt.](https://millionrounds.com/company/inspecity) InspeCity, also known as InspeCity Space Laboratories Pvt. *Founded* 2022 Thane, India **$14M** last round Aug 2025
- 12 [**ARC Aerosystems** ARC Aerosystems is a UK-based aerospace startup founded in 2017, originally named Samad Aerospace.](https://millionrounds.com/company/arc-aerosystems) ARC Aerosystems is a UK-based aerospace startup founded in 2017, originally named Samad Aerospace. *Founded* 2017 Bedford, United Kingdom **$12M** last round Oct 2025
- 13 [**Kreios Space** Kreios Space is a Spanish deep-tech startup founded in 2021, specializing in Air-Breathing Electric Propulsion (ABEP) systems.](https://millionrounds.com/company/kreios-space) Kreios Space is a Spanish deep-tech startup founded in 2021, specializing in Air-Breathing Electric Propulsion (ABEP) systems. *Founded* 2021 Vigo, Spain **$9.5M** last round Sept 2025
- 14 [**Firefly Green Fuels** Firefly Green Fuels is a British developer focused on sustainable aviation fuel (SAF).](https://millionrounds.com/company/firefly-green-fuels) Firefly Green Fuels is a British developer focused on sustainable aviation fuel (SAF). *Founded* 2022 Bristol, United Kingdom **$6.2M** last round Nov 2023
- 15 [**Azure Sustainable Fuels** Azure Sustainable Fuels is a fuel company that offers low carbon, sustainable aviation fuel (SAF) production facility.](https://millionrounds.com/company/azure-sustainable-fuels) Azure Sustainable Fuels is a fuel company that offers low carbon, sustainable aviation fuel (SAF) production facility. *Founded* - Calgary, Canada **$3.7M** last round Mar 2024
- 16 [**Spark e-Fuels** Spark e-Fuels is a Berlin-based climate-tech startup founded in 2021.](https://millionrounds.com/company/spark-e-fuels) Spark e-Fuels is a Berlin-based climate-tech startup founded in 2021. *Founded* 2021 Berlin, Germany **$2.4M** last round Jan 2025
- 17 [**Metafuels** Metafuels is a Swiss climate technology company founded in 2019, focused on developing sustainable aviation fuel (SAF) technology known as aerobrew.](https://millionrounds.com/company/metafuels) Metafuels is a Swiss climate technology company founded in 2019, focused on developing sustainable aviation fuel (SAF) technology known as aerobrew. *Founded* 2021 Zurich, Switzerland **$2.2M** last round Apr 2026
- 18 [**FlyORO** Hello there, we are FlyORO - your solution to last-mile Sustainable Aviation Fuels (SAF) blending technologies.](https://millionrounds.com/company/flyoro) Hello there, we are FlyORO - your solution to last-mile Sustainable Aviation Fuels (SAF) blending technologies. *Founded* 2021 Singapore, Singapore **$1.6M** last round Jan 2024
- 19 [**ATOBA Energy** ATOBA Energy is a private company founded in 2024, focused on sustainable aviation fuel (SAF) aggregation and financing.](https://millionrounds.com/company/atoba-energy) ATOBA Energy is a private company founded in 2024, focused on sustainable aviation fuel (SAF) aggregation and financing. *Founded* 2024 Lyon, France **$1.4M** last round Jan 2025
- 20 [**Avioxx** Avioxx is a clean-tech company based in the UK, founded in May 2023.](https://millionrounds.com/company/avioxx) Avioxx is a clean-tech company based in the UK, founded in May 2023. *Founded* 2023 London, United Kingdom **$1.3M** last round Feb 2024
- 21 [**WeSky** WeSky is an aviation technology company based in Vilnius, Lithuania.](https://millionrounds.com/company/wesky) WeSky is an aviation technology company based in Vilnius, Lithuania. *Founded* - Vilnius, Lithuania **$1.2M** last round May 2025
- 22 [**XCF Global** XCF Global is a clean energy company that develops sustainable aviation fuel (SAF) production facilities.](https://millionrounds.com/company/xcf-global) XCF Global is a clean energy company that develops sustainable aviation fuel (SAF) production facilities. *Founded* - Houston, United States **$700K** last round Jan 2026
- 23 [**Thermolic** Thermolic turns agricultural waste into two premium industrial products: renewable syngas and Thermolic Carbon.](https://millionrounds.com/company/thermolic) Thermolic turns agricultural waste into two premium industrial products: renewable syngas and Thermolic Carbon. *Founded* 2021 Denver, United States **$500K** last round Sept 2026
- 24 [**Urban-Air Port** Urban-Air Port, founded in 2019 and based in London, is a leader in the Advanced Air Mobility (AAM) sector.](https://millionrounds.com/company/urban-air-port) Urban-Air Port, founded in 2019 and based in London, is a leader in the Advanced Air Mobility (AAM) sector. *Founded* 2019 London, United Kingdom **$308K** last round Mar 2026
- 25 [**Flux Aviation** Flux Aviation develops and manufactures sustainable powertrains for general aviation operations.](https://millionrounds.com/company/flux-aviation) Flux Aviation develops and manufactures sustainable powertrains for general aviation operations. *Founded* 2021 Warwick, United Kingdom **$307K** last round Mar 2023
- 26 [**Dimensional Energy** Dimensional Energy is a leader in carbon-to-value technology, focusing on transforming carbon dioxide emissions into sustainable aviation fuel (SAF), renewable](https://millionrounds.com/company/dimensional-energy) Dimensional Energy is a leader in carbon-to-value technology, focusing on transforming carbon dioxide emissions into sustainable aviation fuel (SAF), renewable *Founded* 2016 Ithaca, United States **$75K** last round Apr 2025

**Total funding** how the list is ranked

**15 November 2026** updated nightly

**Rounds we track** source: Millionrounds

Companies whose own description names this theme, ranked by the total they have raised in rounds we hold. Nobody pays to be on a list.

## Who backed them?

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## More lists worldwide

[See all](https://millionrounds.com/top-lists?r=Global)

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