"FARNBOROUGH, England — Airplanes are a minor contributor to global greenhouse-gas emissions, but their share is sure to grow as more people travel in coming years — and that has the aviation industry facing the prospect of tighter environmental regulations and higher costs.
The industry has embraced a goal of reaching net-zero greenhouse-gas emissions by 2050. Experts who track the issue are skeptical.
Until the COVID-19 pandemic caused travel to slump, airlines were on a steady course of burning more fuel, year after year. Today’s aircraft engines are the most efficient ever, but improvements in reducing fuel burn are agonizingly slow — about 1% a year on average."