# Aviation propulsion

Jet, turboprop and helicopter engines burning jet fuel or SAF.

Source page: https://www.materialinsights.org/energy/e_aviation/

Conversion and use · Transport systems · No. 114

- Conversion and use
 Conversion and use · Transport systems · Foundation · Energy

Airlines will burn about 104 billion gallons of fuel in 2026, and less than 1% of it will be sustainable.

Chart: Illustration: Aviation propulsion

##### Where it comes from

Chart: Map of where it comes from

A turbofan squeezes air, burns fuel in it and uses the hot gas to spin a big front fan. The best cores now reach about 55% thermal efficiency at cruise, up from about 30% fifty years ago.

##### Three things to know

1. Fan bypass ratios have grown from about 2:1 to about 11:1 in seventy years, because pushing more air gently wastes less energy.
2. Fuel was 25.4% of airline costs in 2025, forecast to jump to 31.4% in 2026 after a jet fuel price spike.
3. An open-fan design under test has a bypass ratio of about 60:1 and targets about 20% better fuel use.

##### The journey

1. 1 **Jet fuel**Kerosene or sustainable aviation fuel loaded
2. 2 **Compressor**Squeezes incoming air to high pressure
3. 3 **Combustor**Fuel burns in the compressed air
4. 4 **Turbine and fan**Hot gas spins turbines driving the fan
5. 5 **Thrust**Air pushed backwards moves passengers and cargo

##### Go deeper pick a tab to open it in full

## Other sections

- [Overview](https://www.materialinsights.org/energy/e_aviation/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_aviation/correlation/index.md)
- [Science and limits](https://www.materialinsights.org/energy/e_aviation/science/index.md)
- [Value chain](https://www.materialinsights.org/energy/e_aviation/valuechain/index.md)
- [Unit economics](https://www.materialinsights.org/energy/e_aviation/economics/index.md)
- [Engineering methods](https://www.materialinsights.org/energy/e_aviation/methods/index.md)
- [Equipment and suppliers](https://www.materialinsights.org/energy/e_aviation/equipment/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_aviation/links/index.md)