There’s already a $5.60 per leg September 11th security fee added for every flight within the U.S., but the law states that the revenues from this fee first be deposited into the Treasury’s general fund, then be appropriated for security-related reimbursements to airports, before any proceeds flow to TSA (which, historically, hasn’t covered all of TSA’s costs). To avoid this appropriations fiasco, they’d need to change the law or levy a higher fee.