UAL Corp. said late Tuesday that traffic at its subsidiary United Airlines fell 4.1 percent as a result of higher fuel costs and a weaker economy.
The Chicago-based carrier said it flew 9.80 billion revenue passenger miles last month, down from the year-ago month's 10.21 billion. A revenue passenger mile is one paying passenger flown one mile.
The airlines planes are also less full than what they once were; the carrier said its load factor, or percentage of seats filled, dropped to 82.6 percent from 84.6 percent a year ago.
United's capacity also declined 1.7 percent to 11.87 billion available seat miles last month from 12.07 billion in May 2007.
As oil prices continue to swing near $130 a barrel, fuel costs have also risen forcing airlines to raise their ticket prices. As a result, some consumers have decided to defer non-essential travel.