As the airline industry pushes and waits for more sustainable fuels and alternative power engines, many major carriers have shifted focus to the emerging field of studying contrails, once considered an innocent byproduct of water vapor at high altitudes. But those whispy clouds are actually a significant environmental detriment because they hold heat in the atmosphere that would otherwise escape. [...]

The initial trial tested 70 flights, modifying flight paths to try to avoid conditions with altitudes, weather and humidity where they thought contrails were most likely to form. They were able to cut down on contrail coverage by about 54%, based on Google's satellite imagery. But those flights had to use about 2% more fuel to gain the results.