How the first trial went
Google and Cathay Pacific announced on September 7 that they were expanding trials of technology that predicts the formation of persistent contrails. In the first phase, pilots on more than 80 flights used recommendations for small altitude adjustments to avoid cold, humid areas of the atmosphere. [1 · Google] [2 · Cathay Pacific] [3 · Reuters]
The companies estimate that the selected routes reduced the warming effect of contrails by approximately 40%. This is a calculated trial result, rather than a direct measurement of a long-term change in global temperature. [1 · Google] [2 · Cathay Pacific] [3 · Reuters]
What changes in the second phase
Cathay Pacific became Google’s first commercial airline partner in the Asia-Pacific region and the first airline to test contrail avoidance on ultra-long-haul flights. The next phase will cover the carrier’s Asian and transpacific network. [1 · Google] [2 · Cathay Pacific] [3 · Reuters]
The forecasts combine weather and satellite data with AI models. They do not control the aircraft independently: recommendations must be compatible with flight safety, air traffic control restrictions and crew decisions. [1 · Google] [2 · Cathay Pacific]
Sources
- Google — contrail avoidance trial — September 7, 2026
- Cathay Pacific — joint trial with Google — September 7, 2026
- Reuters — expanded Google and Cathay Pacific trials — September 7, 2026
Expert commentary
The approach’s advantage is the possibility of reducing the climate impact of the existing aircraft fleet without replacing fuel or engines. But a small altitude adjustment sometimes increases fuel consumption, so its usefulness depends on the overall balance between additional carbon dioxide and avoided contrail formation. [1 · Google] [2 · Cathay Pacific] [3 · Reuters]
The key data from the second phase will be the number of flights, fuel consumption, forecast accuracy across weather regions and the share of recommendations crews were able to follow. Those figures will show whether the experiment can become a routine flight procedure. [1 · Google] [2 · Cathay Pacific] [3 · Reuters]