suitable airports that do not have tower data link services. (b) Airport selection (1) In general The Administrator shall designate 5 suitable airports for participation in the program established under subsection (a) after consultation with the exclusive representatives of air traffic controllers certified under section 7111 of title 5, United States Code, airport sponsors, aircraft and avionics manufacturers, MITRE, and aircraft operators (2) Airport size and complexity In designating airports under paragraph (1), the Administrator shall designate airports of different size and complexity. (c) Program objective The program established under subsection (a) shall address and include safety, security, and operational requirements for mobile clearance delivery at airports and heliports across the United States. (d) Report Not later than 1 year after the date on which the program under subsection (a) is established, the Administrator shall submit to the appropriate committees of Congress a report on the safety, security, and operational performance of mobile clearance delivery at airports pursuant to this section and recommendations on how best to improve the program. (e) Definitions In this section: (1) Mobile clearance delivery The term mobile clearance delivery means the delivery of access to departure clearance and clearance cancellation via internet protocol via applications to pilots while aircraft are on the ground where traditional data link installations are not feasible or possible. (2) Tower data link services The term tower data link services means communications between controllers and pilots using controller-pilot data link communications. (3) Suitable airport The term suitable airport means towered airports, non-towered airports, and heliports. 615. Study on congested airspace (a) Study Not later than 270 days after the date of enactment of this Act, the Comptroller General shall initiate a study on the efficiency and efficacy of scheduled commercial air service transiting congested airspace. (b)