When is "Sustainable Aviation Fuel" not sustainable?

In a decision that will cause more concern than ever for airlines seeking to advertise their environmental credentials, the UK's regulator of advertising, the Advertising Standards Authority (the "ASA") has ruled that Virgin Atlantic's radio advert concerning "Flight100" was misleading and breached the UK Code of Broadcast Advertising ("BCAP Code") and UK Code of Non-broadcast Advertising and Direct & Promotional Marketing ("CAP Code"). 

This article scrutinises the ASA's decision in more detail and identifies the most important lessons for airlines concerned with allegations of greenwashing (for those in a hurry, go to section 4 to see these now). It also queries whether the approach taken by the ASA in this case is realistic or appropriate in the context of a modern aviation industry that is striving towards improving sustainability and achieving Jet Zero by 2050.