The fresh air of the snow-covered Swiss mountains reverberated to the howl of private jet engines earlier this year as the planet's movers and shakers descended on Davos for the annual World Economic Forum.
원문출처 : https://www.cnn.com/travel/article/sustainable-aviation-fuel-greener/index.html
원문출처 : https://www.cnn.com/travel/article/sustainable-aviation-fuel-greener/index.html