[throwaway894345]

I'm strongly in favor of a carbon tax, but the margins on airlines are already so thin that it's possible that increasing the costs significantly can make them unviable (barring some innovation in carbon-neutral transit, such as these airships). Specifically, a carbon tax could push ticket prices up so far that few can afford them, and since costs are amortized over many passengers, sharply reducing the number of passengers would further drive up the costs per passenger, in turn pushing ticket prices out of reach of even more people. It's possible that commercial air travel becomes altogether unviable such that air travel is only available to those who can afford private jets.

Of course, we wouldn't allow that to happen, so we would subsidize the airlines, which in turn defeats the purpose of the carbon taxes.

Now, you might say, "carbon taxes will drive the industry to find economical, carbon-neutral solutions", and surely it will provide this motivation, but motivation alone doesn't guarantee that such a solution exists or that we will find it in time.