On two flights between the U.S. and Europe, United Airlines plans to demonstrate new fuel- saving methods on Saturday.

United expects to save about 940 gallons of fuel. The carrier would usually burn about three percent of the fuel on flights. The testing includes a flight from Frankfurt to Chicago on a United 777 and a return trip on the same plane. Both will be normal flights with paying passengers.

Usually, commercial flights remain at an exact altitude. This flight will instead fluctuate up and down as much as 3,000 feet. By doing this, pilots won’t need to burn extra fuel maintaining a precise elevation.

In addition, it allows pilots to choose the best altitude depending on wind and other conditions, said Joe Burns, a United captain and managing director of technology and flight tests.

According to Burns, these changes won’t make too much of difference on a short domestic flight but will help on an international flight of eight to 10 hours.

Source: ChicoER