Kroo

But a group of researchers at Stanford University, led by Ilan Kroo, has suggested that airlines could take a more naturalistic approach to cutting jet-fuel use and it would not require them to buy new aircraft.

Dr Kroo and his team modeled what would happen if three passenger jets departing from Los Angeles San Francisco and Las Vegas were to assemble over Utah,assume an inverted V-formation, occasionally change places so all could have a turn in the most favour

Dr Kroo points out that the aircraft could be separated by several nautical miles, and would not be in the intimate groupings favoured by display teams like the Red Arrows.

Dr Kroo says this is one of the areas his team will investigate further.

The answer, says Dr Kroo, lies with birds.