Heathrow Airport’s chief executive, Thomas Woldbye, revealed a surprising cause of crowding: British and European travelers walk on different sides and often bump into each other. Speaking at an Aviation Club UK event, he said, “The problem is that all the British people keep to the left and normally Europeans keep to the right. And they do that in both directions.” Woldbye added, “So we can be crashing into each other, and I see that from personal experience.” He explained that Terminal 5, used mostly by British Airways, feels crowded partly because people are “in the wrong place.” He suggested a simple fix: “We just need to make sure that everybody going this way keeps to the left and this way to the right.” Heathrow plans to add a third runway, which could bring 40 million more passengers yearly. Yet Woldbye warned that even with expansion, London might lose market share to other airports for the next decade due to faster growth elsewhere. Heathrow is also tackling environmental concerns by boosting sustainable aviation fuel (SAF) use. The airport set up an £80 million fund to help airlines pay the higher cost of cleaner SAF, aiming for 5.6% SAF use by 2026, above the UK’s 3.6% mandate. SAF, made mostly from recycled cooking oil, reduces carbon emissions over its lifecycle. "We have looked to use our scale and influence to attract SAF and we’ve shown you can get SAF flowing," said Matt Gorman, Heathrow’s director of sustainability. Industry leader Duncan McCourt said government targets to build five UK SAF plants by 2025 were “optimistic,” but progress exists. He highlighted the economic benefits of SAF, including tens of thousands of UK jobs by 2050. Recent data showed the UK met its first SAF mandate of 2% fuel for 2025, with a rush of SAF use in late 2023. Heathrow's challenges show how even simple habits and big climate goals shape the future of air travel.