> I am always curious what happened to the realization that air travel is a multitude worse than any other type of air pollution because it essentially directly delivers harmful particles right into the highest strata of our atmosphere. Is that no longer a concern with the jet-setting, globe trotting liberals?

https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...

"The IPCC has estimated that aviation is responsible for around 3.5% of anthropogenic climate change, a figure which includes both CO2 and non-CO2 induced effects. The IPCC has produced scenarios estimating what this figure could be in 2050. The central case estimate is that aviation’s contribution could grow to 5% of the total contribution by 2050 if action is not taken to tackle these emissions, though the highest scenario is 15%."

So, it's a concern, but far from the largest. There have been pretty significant advances in fuel efficiency, lighter aircraft, stuffing more people into a single plane, etc.