West Coast, perhaps the hot sun is getting to be too much out there!
If "market forces" were made to pay for everything, your ticket costs would be astronomical, and airline travel would be decimated. Think of the resulting economic fallout worldwide.
In financing most modes of mass transportation, e.g., rails, highways, and seaports,not to mention airports, governments play a large role because they see a strong transportation system as vital to national interests.
Indeed,in today's global economy, transportation is becoming more important daily. Look at the projected growth of the Chinese civil air fleet. Who do you think is building their airports, the concession shop owners?
Don't worry so much about what your taxes finance today.
Why? Some see the biggest threat to the developed economies will be not terrorism, but oil nationalism. If that reaches a tipping point,and significant amounts of oil to the US are cut off, your tax dollars will be entirely insufficient for anything, and your "market forces" will likely leave you living in a tent on San Francisco Bay, wondering what happened.
If you're so still so worried about use of your tax dollars, you might complain in another forum about the Hurricane Katrina and Iraq War tax boondoggles, extractive industry tax breaks, etc. etc. etc.