(a) If, in any fiscal year, appropriations for payments to air carriers remain at or below the amounts estimated as necessary to maintain subsidy-supported essential air service at the places receiving such service, and Congress provides no statutory direction to the contrary, appropriations shall not be available for essential air service to otherwise eligible places within the 48 contiguous States and Puerto Rico that have a rate of subsidy per passenger in excess of $200.00, or are located:
(1) Less than 70 highway miles from the nearest large or medium hub airport;
(2) Less than 55 miles from the nearest small hub airport; or
(3) Less than 45 highway miles from the nearest nonhub airport that has enplaned, on certificated or commuter carriers, 100 or more passengers per day in the most recent year for which the Department has obtained complete data.
(b) The rate of subsidy per passenger shall be calculated by dividing the annual subsidy in effect as of July 1 of the prior fiscal year by the total origin-and-destination traffic during the most recent year for which the Department has obtained complete data.