Public Refuses to Fly Without Discount Fares : Transportation: It’s a vicious cycle. Airlines. slash prices to sell tickets, increasing their already huge losses, which forces them into yet another price cut.

With their constant fare wars, airlines have painted themselves into the same corner that’s trapped many retailers: Consumers won’t buy unless they see a “sale” sign, travel-industry experts said Monday.

Intense competition among the airlines, which collectively lost $6 billion over the last two years, still prompts one carrier to start offering huge discounts other airlines are forced to match.

Northwest escalated the latest price battle Sunday, saying it will cut fares to its five European destinations by as much as 44%. Tickets must be purchased by Sept. 4 for travel between Nov. 1 and March 31, 1993.

United, Trans World Airlines and Delta generally said they will match the cuts in competitive markets. American said Monday it will extend the lower prices to all its European routes--a move United said it will match in competitive markets. TWA and Delta said they will consider similar action.

The Northwest move came after Delta sliced fares to Europe between 10% and 40% and most airlines followed. Delta and other carriers have also said they will cut fares in the United States by about 30% for travel this fall.

Half-price ticket sales this summer erased the possibility of profit at the peak travel time, which is supposed to help airlines make it through weak fall and winter quarters. Second-quarter profits were among the worst ever for the airlines.

“The aviation industry is training the public to wait for a ‘sale’ sign,” said Philip Davidoff, president of the Alexandria, Va., American Society of Travel Agents. “People are pushing forward their buying plans.”

Indeed, fall and winter bookings this year are unusually low, partly because the 50% sale enticed passengers to fly in the spring and summer rather than the colder months.