United We Fall?

United Airlines claim they will be '100% green by 2050' (https://www.theguardian.com/environment/2021/dec/29/united-airlines-sustainable-green-flying-experts). United's only tinge of green thus far, is a single passenger flight from Chicago to Washington. This was carried out using so-called 'Sustainable Aviation fuel' (SAF). SAF is made from cooking oil and agricultural waste. United described the flight as 'a significant milestone' in the effort to decarbonise the airline industry. They suggested that it heralded the development of 'guilt-free' flying. Although, SAF may replace traditional fossil fuels, it has considerable problems. Firstly, SAF is unlikely to ever be scaled up sufficiently, to actually replace kerosene. Secondly, burning it, still pumps masses of 'greenhouse gases' high into the atmosphere. Some must also note that United (and some other airlines) are intent on increasing flight numbers and adding destinations. They even intend to develop supersonic air travel, utilising yet more energy and flying even higher. Clearly, air travel can never be 100% green. Reducing air travel emissions, fast enough to deal with global heating, can only be achieved by having fewer flights. Most of the people on this planet are not frequent fliers but will be impacted by climate change.