U.S. airlines in March achieved an 11.5 percent year-over-year increase in domestic passenger yield to 16.75 cents per mile

, according to the Air Transport Association. Defined as "the average price (excluding taxes) paid to fly one mile," domestic yield for March increased by a greater margin than in any month since July 2010. ATA also reported that U.S. airlines during March collected 13 percent more revenue than a year earlier and increased systemwide traffic by 1 percent. "The revenue growth experienced in the first quarter has not been sufficient to keep pace with higher jet fuel costs, which have risen more than 30 percent from a year ago," according to ATA chief economist John Heimlich. "The airline industry remains concerned about a possible slowdown in demand induced by rising energy prices across the economy."