More airfare hikes

Delta Air Lines Inc., the nation's third-largest carrier, said Monday it raised domestic fares in most cases $10 to $40 per roundtrip, in the form of a fuel surcharge. The Atlanta-based carrier increased a fuel surcharge added to tickets by $10 to $40 round trip, depending on the type of airfare. The increase brings the fuel charge on some tickets to $110 round trip, Delta said.

Northwest Airlines Corp. and US Airways said they were studying the fare hike.

Airlines have been hiking fares in recent months to deal with soaring fuel prices, spurred by oil, which currently stands at nearly $120 a barrel. Some fare increases have stuck, while others have not.