For those of us who love to travel, climate guilt weighs heavily. Civil aviation accounts for about 3% of global greenhouse gas emissions, and that number is going up. But while electrifying cars and trucks is already well underway, flying planes on anything other than liquid fuels remains devilishly difficult. Despite that difficulty, there are options. Sustainable aviation fuels, or SAFs, hold the most promise, as they can theoretically drop right into existing engines and infrastructure. Beyond that, a number of startups are tinkering with electric battery-powered aircraft, as well as hydrogen-powered electric planes. But how sustainable are these options, and are they really ready for prime time?  Guests: Fred Ghatala, Director of Carbon & Sustainability, Advanced Biofuels Canada  Stephanie Searle, Fuels Program Director, ICCT Scott Cary, Project Manager, NREL  Christina Beckman, Co-creator, Tomorrow’s Air; Vice President, Adventure Travel Trade Association Learn more about your ad choices. Visit megaphone.fm/adchoices