A recent study by the National Center for Atmospheric Research discovered that the communities near large, busy airports received more precipitation than surrounding regions. Why so?
Well, scientists speculate that the rapid compression and expansion of air around turboprop propellers chills and condenses the water vapor in the air creating (depending on the season) snow or rain.
Could air travel have an effect on global precipitation — and climate in general? Not really. Given the enormous volume of air that comprises the atmosphere*, the influence of air travel is (you might say) a drop in the bucket.
It didn’t appear that the researchers looked at the air compression / expansion caused by air flow around the wings of a plane, but I believe that could play a role too.
*In case you’re curious, and if I did my math correctly, the volume of air in the atmosphere is 4.18 billion cubic kilometers…give or take.