Moving in a pack by day's end, several U.S. airlines yesterday announced plans to raise fares in the wake of rising fuel costs spawned by the Middle East crisis.

Industry leader American Airlines said it would increase fares by 10 percent beginning tomorrow on domestic flights and next Wednesday on international travel. Because of American's size and economic health, it had been considered a key obstacle in the bid to raise fares, launched by Pan Am, Northwest and Trans World Airlines earlier this week.

Within hours of American's announcement, Chicago-based Midway Airlines said it would match American's increase beginning tomorrow, and Phoenix-based America West Airlines said it would increase most of its fares by up to 10 percent. The Trump Shuttle also said one-way fares for its Washington-New York-Boston flights would climb $10 beginning Monday, to $129 at peak times and to $89 on weekends.

Officials at the Pan Am Shuttle and Delta, United, Eastern, USAir and Continental airlines said they had no immediate plans for increases, but that the situation could easily change. Delta Airlines issued a statement advising passengers to "purchase tickets now" because increases are likely.

"If crude holds at $25 a barrel," said George W. James, chairman of the consulting firm Airline Economics, "it's going to mean that instead of a $500 million {combined} operating profit for airlines this year, there will be a $1 billion loss even if the airlines succeed in passing some of the costs on."

Helane Becker, analyst with Lehman Bros., said she expected all airlines to follow through with increases, but that because of weak traffic, hikes could not likely be sustained.

The airlines weren't the only ones trying to pass on the costs of escalating fuel prices. The trucking industry sought and gained permission from federal regulators to temporarily raise the prices it charges to customers with only three days' notice rather than the usual seven-day notice. Those higher rates would likely result in higher price tags on everything from clothing to food, according to industry executives.