A handful of studies have concluded that making minor adjustments to the routes of a small fraction of airplane flights could meaningfully reduce global warming. Now a new paper finds that these changes could be pretty cheap to pull off as well.

The common climate concern when it comes to airlines is that planes produce a lot of carbon dioxide emissions as they burn fuel. But jets also release heat, water vapor, and particulate matter that can produce thin clouds in the sky, known as “contrails,” in particularly cold, humid, icy parts of the atmosphere.