a company called Fuel Matrix says it's in talks with UK airlines to calculate exactly how much fuel planes need to fly, by simply weighing the people before they get on the airliner.

This data could then be passed directly to the flight deck for pilots to work out precisely how much fuel their plane needs.

Chief operating officer Nick Brasier told the Independent that most flights carry about one per cent more fuel than they need and burn about 0.3 to 0.5 per cent more fuel due to the extra fuel weight.

https://www.dailymail.co.uk/travel/travel_news/article-6936237/Is-weighing-passengers-flights-off.html