American Airlines and Google say AI helped airplanes reduce contrails that trap heat

American Airlines and Google have reported significant climate impact reductions through an innovative AI-powered contrail prevention system, according to a joint announcement released Thursday.

The collaborative trial targeted condensation trails—commonly known as contrails—which form when aircraft exhaust particles create ice crystals in cold, humid atmospheric conditions. These seemingly innocuous white lines trailing behind aircraft actually contribute between 1-2% of the Earth’s total warming, according to research from Contrails.org, a nonprofit organization founded under Bill Gates’ Breakthrough Energy initiative.

The program leveraged Google’s artificial intelligence to forecast where contrails would likely form, incorporating these predictions directly into American Airlines’ flight planning systems. This allowed pilots to make minor altitude adjustments or route modifications to avoid atmospheric conditions conducive to contrail formation.

“We know that aviation is one of the hardest, most difficult sectors to decarbonize,” explained Dinesh Sanekommu, who leads Google’s contrail research, in an interview. “We think there’s a way that AI can help make that a reality.”

The scale of the trial was substantial, involving 2,400 flights operating between the United States and Europe. Half of these flights were given optional routing to avoid contrail formation, while the other half served as a control group for comparison. Among the 112 flights that utilized the alternative routing options, contrail formation decreased by 62% compared to the control group.

Researchers estimate this reduction translated to approximately 69% less climatological warming from those specific flights. Importantly, the trial found no statistically significant difference in fuel consumption between the groups, addressing a primary concern for airlines considering such measures.

The North Atlantic region, where the trial took place, is particularly prone to contrail formation, making it an ideal testing ground. The trial ran from January through May 2025 and included collaboration with Flightkeys, American Airlines’ flight planning service provider.

Aviation industry observers have noted the significance of this approach. Unlike other decarbonization strategies like sustainable aviation fuel—which can substantially reduce emissions but comes with significantly higher costs—contrail avoidance through minor route adjustments represents a potentially cost-effective climate solution that could be implemented immediately.

Thomas Walker, who researches aviation climate impacts at the Clean Air Task Force, called the American Airlines trial “a pretty big step in the right direction” and the largest such initiative he’s aware of in the United States. Similar trials have been conducted in European airspace.

“There’s been a little bit of pushback,” Walker noted, citing challenges in coordinating between pilots and air traffic controllers across different international airspace regions. However, American Airlines’ Jill Blickstein, vice president of sustainability, countered that the trial demonstrated dispatchers and pilots could readily file and fly alternative plans to avoid contrail formation.

The trial builds upon previous collaborative work between Google, American Airlines, and Breakthrough Energy from 2023, though that earlier effort relied on manual flight identification rather than direct integration with flight planning systems.

Looking ahead, Sanekommu indicated the need for larger-scale trials and expressed interest in working with additional flight planning software providers to incorporate contrail forecasting and avoidance features into their products.

Despite the promising results, American Airlines has not yet committed to making contrail avoidance a standard component of its regular flight planning process. The airline indicated it hopes to continue partnership research, potentially exploring different routes and flight times to answer remaining scientific questions.

As the aviation industry faces mounting pressure to address its climate impact, this AI-driven approach to contrail mitigation represents a potentially significant advancement that combines cutting-edge technology with practical operational changes to reduce the sector’s environmental footprint.