Virgin Atlantic Flies First TransAtlantic Low Carbon Crossing. Is SAF a Gaffe?

SAF or “Sustainable Aviation Fuel” as described here, leaves me with a whole lot of questions.
Some of it comes from kitchen grease, of which there is nowhere near enough. Some comes from biomass. What biomass? from where?
Biomass is something we’re trying to get away from in large scale power generation. Why is it a good idea here?
Also, ethanol. Not even close to a solution now. Not seeing how it suddenly becomes a better idea to feed it to jets.

Reuters:

A Virgin Atlantic (VA.UL) passenger jet powered by 100% sustainable aviation fuel (SAF) completed a London-to-New York jaunt on Tuesday, showcasing the potential of low-carbon options, which are a tiny fraction of the industry’s fuel mix.

The flight is not the first time the industry has staged demonstrations to highlight its aspiration to reduce emissions – and appeal for government support. Indeed, Tuesday’s flight carried only Virgin’s billionaire founder, Richard Branson, and a few others, and it is set to return to London using conventional jet fuel.

Airlines are banking on fuel made from waste to reduce their emissions by up to 70%, but the high cost and tight supply of materials needed to make SAF make large-scale production difficult. SAF accounts for less than 0.1% of total global jet fuel in use today and costs three to five times as much as regular jet fuel.

The flight, operated by a Virgin Boeing (BA.N) 787 powered by Rolls-Royce (RR.L) Trent 1000 engines, is the first time a commercial airliner has flown long haul on 100% SAF. It had no paying passengers or cargo.

“It’s going to take a while before we can get enough fuel where everybody’s going to be able to fly. But you’ve got to start somewhere,” said Branson in London before the plane took off.

Aviation is not an easy industry to decarbonize compared to road travel, and it accounts for an estimated 2-3% of global carbon emissions.

Engines in commercial use are not yet certified to fly on more than 50% SAF and the vast majority of flights blend in a much lower amount of SAF with traditional jet fuel.

SAF is already used in jet engines as part of a blend with traditional kerosene, but after successful ground tests, Virgin and its partners Rolls-Royce, Boeing (BA.N), BP (BP.L) and others won permission to fly using only SAF from the U.S. Federal Aviation Administration, Canadian and UK regulators.

The flight took off at 1149 GMT from London’s Heathrow Airport with Branson, Virgin Atlantic Chief Executive Shai Weiss and Britain’s transport minister, Mark Harper, on board. It landed at New York’s John F. Kennedy International Airport at 1405 EST (1905 GMT), 35 minutes early, where it was met by U.S. Deputy Transportation Secretary Polly Trottenberg, among others.