We must fly less. I am flying less; I use train and bus. I only take a plane for more than 1,000 miles.
In 2008 I went from Newark, New Jersey to Richmond, Virginia by bus to meet my supervisor. The bus took 9 hours each way, but I did not pollute as much as in a plane. Of course I flew from Lisbon, Portugal to Newark in a single, nonstop flight.
Mathematics professor
https://publons.com/researcher/1206831/jorge-santos/metrics/