I think the way airline tickets are priced is a big factor, and needs to change.

It is often cheaper to take a connecting flight to an airport and flying from there than to start from that airport. That disincentivises taking a low-carbon-emission train to the airport and experiencing more of (and spending more in) the city near the airport than just its airport.

Often, for longer flights, the more stops, the cheaper the total ticket gets. Planes consume more fuel at take-off and landing, making the the carbon footprint increase with these cheaper tickets. And the more you fly, the more points you get that could pay for more flights.

It should be the other way around: air-travel carbon tax should be progressive. You should pay more each time if you fly more often. That would reduce the number of flights in total while still allowing everyone to take that "trip of a life-time".