The main purpose of the Reimbursable Screening Services Program Extension Act of 2026 is to extend and expand a program that allows for reimbursable screening services by the Transportation Security Administration (TSA). This program is designed to enhance security measures at airports and other transportation facilities, ensuring that they can effectively manage security screenings while also providing flexibility in funding. Key provisions of this act include an extension of the program's duration from 2026 to 2031, allowing it to continue operating for an additional five years.