I estimate the Internet's effect on the level and dispersion of airline fares on a given route within and across firms. The results suggest that increases in Internet penetration reduce average price and lead to higher intrafirm price dispersion, while increases in Internet penetration do not affect interfirm price dispersion on a given route. Internet penetration affects average fares most in competitive markets. These results suggest that the Internet has significantly but subtlely influenced domestic airline competition. The effect of the Internet on prices and price dispersion is larger on direct flights.