I start in a similar place but go the other direction. Airline travel is an important personal luxury, and crucial to global business or politics. While in the ideal it may be unnecessary, you’re not going to get people to give it up willingly, and they’d argue there’s no other option for such travel. So, what can we do?

The industry is great at adopting efficient technology but it can’t even keep up with growth in demand, much less reduce carbon emissions. So what else can we do?

1. We need to drive/incent/require widespread usage of Synfuel/biofuel. At least then you’re just moving carbon currently active in the carbon cycle, rather than adding yet more carbon that’s been sequestered for hundreds of millions of years.
2. Trains. We need to spend a lot more on trains. In this case we need to give people a more climate friendly option for travelling between cities up to 500 miles or so apart. We need trains to replace every short flight, so the carbon emissions from flying are at least only spent when there’s no other option. I read that France has started with bans on flights between a few cities with good rail service. Here in the US, we’re way behind with high speed rail but Acela is good enough to replace flying between a few cities, like Boston to NYC