Since the Wright brothers successfully flew a motor-operated airplane on the shores of North Carolina in 1903, people have looked up to the skies to open the world and push the boundaries of progress. Aviation has come a long way from the early days. Every day, about 100,000 commercial flights take off and land around the globe. Add in private jets, military planes, and other forms of flight – including space flight – and the total picture is staggering.
The airplane is undoubtedly one of humanity’s greatest innovations. Nonetheless, aviation is at an inflection point. As global economic growth spurs greater demand for air travel, it remains one of the dirtiest parts of the global economy. Safely and reliably, flying hundreds of people is hard and expensive no matter what, and fossil fuels are the easiest way to put planes in the sky.
About 20-40% of the cost of a typical flight is reserved for fuel. Most commercial planes burn several thousand gallons of fuel while flying. Today’s jets are much more fuel-efficient than their predecessors, but the bottom line is that it takes a lot of energy to lift a commercial airplane and keep it in the sky for hours on end. Up until now, with very few exceptions, all of that fuel has been some sort of fossil fuel. The result? Aviation contributes 4% to human-induced global warming and is projected to cause about 0.1 degrees Celsius (0.2 degrees Fahrenheit) of warming by 2050 if the industry keeps growing at pre-pandemic rates. If aviation were a country, it would be the world’s sixth-biggest emitter.

For many of the world’s major economic activities, replacing fossil fuels with cleaner alternatives is technically simple. Consumer technologies like electric vehicles and heat pumps perform similarly or better to their conventional (and dirty) counterparts while being either comparably intricate or simpler in terms of fundamental technology. As such, they’re also becoming cheaper and more popular. Electrification and other forms of innovation can make decarbonization fairly easy for the vast majority of the global economy. But many activities aren’t so easy to decarbonize. Aviation is one of them.
Why is that? Above all, flying a typical commercial plane – let alone a smaller plane – thousands of miles requires a lot of energy. Fossil fuels are energy-dense, so even though fuel adds weight to the plane, it’s still economical. Nonetheless, airliners worldwide are looking down the runway at a fossil-free future that will hinder their current business models. If they want to remain profitable without excessively polluting the skies, they must innovate.