BTS, in a release of preliminary data, reported that U.S. airlines carried 8.6 percent fewer domestic passengers than in May 2008. International passengers on U.S. carriers decreased 14.8 percent, the biggest percentage decrease from the same month of the previous year since Dec. 2001.

For the first five months of 2009, the number of scheduled domestic and international passengers on U.S. airlines declined by 9.5 percent from the same period in 2008, dropping to 281.9 million, 29.5 million fewer than a year earlier, and the lowest January-to-May total since 2004.

U.S. airlines carried 9.4 percent fewer domestic passengers and 9.8 percent fewer international passengers in the first five months of 2009 than during the same period in 2008.