N.Y. Comp. Codes R. & Regs. tit. 21, § 1263.5 – Porter service charges.

(a) For each passenger embarking upon and for each passenger disembarking from an aircraft at the International Arrival and Airline Wing buildings (whether or not such passenger actually uses porter service) .50
Such charge shall not be payable in connection with aircraft using the ramps adjacent to the International Arrival and Airline Wing buildings only for the purpose of picking up or delivering passengers embarking upon or disembarking from flights of the airlines using such buildings.
(b) Such charge shall not be payable in connection with passengers on sightseeing flights (by which is meant flights on which passengers are carried for hire and which originate and terminate at the air terminal with no intermediate stops other than emergency stops), and which flights are conducted under permit from the Port Authority; and such passengers shall not be included in the computation of the average cost per passenger of porter service hereunder.
(c) Such charge shall not be payable in connection with passengers who disembark from an aircraft which has returned to the airport subsequent to take-off and prior to its first scheduled stop because of mechanical or other difficulties and who subsequently embark upon the same or a substituted aircraft without requiring porter service.
(d) Such charge shall not be payable in connection with aircraft using the ramps adjacent to such buildings merely to pick up or deliver passengers embarking upon or disembarking from flights of the airlines using such buildings.