About 100,000 Flights Jet around the world every day. Flying accounts for 2. 5 of all carbon emissions. Now, that might not sound like much, but if aviation was a country, it would be among the top ten most polluting nations in the world, and its impact is expected to rise. Now theres a global race to get clean aviation off the ground. And some companies think theyre close to cracking it. Pretty soon, passengers will be flying in zero emission aircraft. But how did we get here