; (2) barriers to entry into the aviation workforce; and (3) options to increase the future supply of individuals in the aviation workforce. (c) Submission Not later than 1 year after the date of enactment of this Act, the Comptroller General shall submit to the Committee on Transportation and Infrastructure of the House of Representatives and the Committee on Commerce, Science, and Transportation of the Senate a report on the results of the study, including any findings and recommendations. 599B. Metropolitan planning organizations Section 134(d)(4) of title 23, United States Code, is amended by striking Nothing and inserting Except with respect to a metropolitan planning organization whose structure consists of no local elected officials, nothing . 599C. Study (a) In general Not later than 6 months after the date of enactment of this Act, the Comptroller General of the United States shall begin a study of international air cargo services among the United States and Central American, South American, and Caribbean Basin countries, that— (1) analyzes the supply of and demand for air cargo transportation services among the United States and Central American, South American, and Caribbean Basin countries; (2) analyzes the supply of and demand for air cargo transportation services between— (A) the United States, Central American, South American, and Caribbean Basin countries; and (B) Africa and Europe; (3) identifies the busiest routes in terms of cargo capacity and frequency of air service; (4) identifies any air carrier or foreign air carrier hubs in Central American, South American, and Caribbean Basin countries at which a significant amount of air cargo is sorted, handled, or consolidated for transportation to or from the United States