Do you mean "majority of the voting public", rather than "majority of the traveling public"? A lot of voters do not travel (much), and do not live in areas that receive a lot of visitors (and the economic boost of their spending).
Depends more on how you get to the "majority." If each person who travels at all during a year counts once then yes, the majority likely support the TSA in their current incarnation, or at least are not opinionated about it. If you count each time someone passes though a checkpoint then frequent fliers get more votes and the numbers are skewed dramatically.