The aviation industry is vital to the U.S. economy. Passenger airlines directly generate billions of dollars in revenues each year and communities depend on passenger airlines to help connect them to the national transportation system. Between 2002 and 2013, jet fuel prices more than quadrupled from $0.72 to $2.98 per gallon and general aviation gasoline prices more than tripled from $1.29 to $3.93 per gallon in nominal terms. The Airport and Airway Trust Fund (trust fund) is funded principally by excise taxes on ticket purchases, aviation fuel, and cargo shipments as well as interest revenue. Section 808 of the FAA Modernization and Reform Act of 2012 required GAO to study the impact of increases in aviation fuel prices on the trust fund and the aviation industry in general. This report discusses (1) the impact of increases in fuel prices from 2002 to 2013 on commercial passenger aviation, (2) the impact of increases in fuel prices from 2002 to 2012 on general aviation, and (3) the results of GAO's analysis of how future increases in fuel prices could impact the trust fund. GAO reviewed studies and other literature on the impact of fuel price increases. GAO conducted an analysis that included scenarios with increases in fuel prices up to 200 percent (as mandated by Section 808) through 2024. GAO also interviewed government officials and aviation associations. GAO is not making any recommendations in this report.