Re: “Airbus bets on hydrogen to deliver zero-emission jets” [Dec. 6, Business]:

Non-carbon alternatives currently exist for all major uses of fossil fuel except for air travel. Airbus hopes that hydrogen fuel can be produced using renewable energy. It is critically important that the complete life cycle of a fuel be carbon-free. There is a lot of talk about sustainable aviation fuels, but what is available still produces carbon emissions in its production or use.

Flying is a major contributor to global warming. Until we have carbon-free alternatives, we all need to fly less.

Laura Gibbons, Seattle