Airline pilots flying slower to save fuel
This is saving the aviation industry money and helping carriers fend off criticism from the environmental lobby by cutting carbon emissions.
Pilots find that, like car drivers, taking their "foot off the gas" can lead to big savings.
In some cases airlines rely on computer technology similar to cruise control in luxury cars to find the most fuel-efficient speed.
This is the option taken up by British Airways.
"Optimum speeds are selected throughout each flight and fuel is conserved," said a BA spokesman.
Many airlines aim to glide planes in to land, rather than bringing them down in stages.
Friends of the Earth gave a lukewarm welcome to the initiative.
A spokesman for the environmental campaign group said: "Every little helps, but it is really only going to make a small difference."