Within 20 years, there will be roughly twice as many planes in the sky and more than twice as many passengers.
Even after decades of climate warnings, aviation is not slowing down. It is speeding up. The number of airline passengers grew by 5.3% in 2025. More passengers means more planes: the world’s fleet is forecast to roughly double by 2044, from about 23,000 aircraft today to over 45,000, each one built to burn jet fuel for another 25 years or more.
And the industry is only getting started. Around 80% of the world’s people have never flown, and to the airline industry, that is an exciting untapped market.
All aviation markets are growing
Growth is continuing across the board despite the aviation industry’s climate commitments. Passenger numbers are set to more than double over the next 20 years, and the fleet to roughly double with them.
Mature aviation markets, like the UK, are still expanding. London has six international airports, the busiest city airport network in the world, and they are planning further expansion.
Developing markets are growing even faster. India’s fast-rising middle class is ready to take to the skies: the country plans 50 new airports over five years, and Indian airlines have ordered well over 1,000 new aircraft from Boeing and Airbus since 2023.
And the cost of all this expansion is not only the climate. Every new runway and flight path means more noise and dirtier air for the communities living beneath them, communities that, more often than not, fly the least.
This is the growth that every one of the industry’s so-called ‘solutions’ is supposed to clean up. As the next pages show, they cannot keep pace.
What can you do?
Growth is built on demand, and demand is built on millions of individual choices, including yours. The most powerful thing you can do is not add to it: fly less, especially the long-haul and the “because it was cheap” trips. And speak up, because we need to challenge unchecked airport expansion.
- Take the Quiz: How Big is Your Bumprint? and share your results.
- Use our Passenger Action Checklist to plan a lower-carbon trip when you need to fly.
- Get Involved, and add your voice against expansion that doesn’t add up.
Your questions:
Growing fast. Airlines expect a record 5.2 billion passenger journeys in 2026, and IATA’s own forecast has demand more than doubling by 2050.
That’s the central tension: you can’t easily decarbonise an industry that plans to double. The sector’s own roadmap leans heavily on sustainable fuel and technology that aren’t scaling anywhere near fast enough.
In the UK alone, expansions adding 60 million-plus passengers have been approved across 10-plus airports, with no cumulative assessment of the combined climate impact, even as official advisers warn aviation is on course to be a top-emitting sector.
As other sectors clean up, aviation’s slice grows: on current UK forecasts it could become the single highest-emitting sector by around 2040.
