This Yahoo Finance article highlights companies using hydrogen power, a long-term green power source:

“Hydrogen, the most common element in the universe, is all around us – highly reactive and non-polluting. When used as a power source in chemical fuel cells, the chief byproduct is simple water. Hydrogen-fueled power systems have the potential to replace a host of combustion engine applications and vehicles.”

Read more at: “The Future of Hydrogen Power Is Here — and These Stocks Are Leading the Charge“

European aircraft manufacturer, Airbus, has developed several concept designs for zero-emission commercial aircraft powered by hydrogen. The concept designs are codenamed ZEROe. According to IATA, commercial aircraft produce up to 3 percent of worldwide carbon emissions. The industry has set ambitious goals to reduce the impact of commercial aviation on climate change such as a 50% reduction of carbon emissions by 2050. The zero-emission aircraft are likely to revolutionize the air transport industry.

Read about these concept aircraft at:
https://www.aviationtoday.com/2020/09/23/new-zero-emission-commercial-aircraft-designs-unveiled-airbus/