The outlook improved yesterday for those who bought low-fare winter flights between the United States and Great Britain.

Some airline officials say they now believe there is a reasonable chance that the 130,000 travelers who have paid for their tickets may be able to use them without paying extra, despite British orders aimed at invalidating the tickets.

"We are optimistic that this will be resolved," said David Venz, a spokesman for TWA (Trans World Airlines). "We don't think it was the intent of the British government to hurt people who purchased tickets in good faith. And we have a little time left yet to work it out. We have until Thursday the first day of the winter travel season ."

Another reason was suggested by some veteran travel agents. "They the British are going to have the wrath of God on them if they don't allow people to travel at that price, and I don't think Britain wants that -- they need that tourist dollar too much," said Linda Meigs, director of travel agency services for the American Automobile Association, the largest U.S. travel agency.

The unprecedented action by British officials raises the ante in their struggle with the United States over American antitrust laws. The liquidators of Sir Freddie Laker's bankrupt Skytrain service have a billion-dollar antitrust suit pending in federal court in Washington, and a federal grand jury is looking into possible criminal antitrust violations in the Skytrain failure.

British officials claim that the low fares for this winter might be used in future antitrust cases, and so they have disapproved them.

Among the travelers caught in the thick of the battle are Susan Hill, a senior at Radford University, and her mother, an AAA agent who lives in Fairfax County.

The women paid $468 each for roundtrip tickets on Pan Am to fly to London to spend Thanksgiving with relatives there. Susan Hill used the savings from her part-time job at Fair Oaks Mall to pay for her ticket and her first trip to England. "I saved $500 for the ticket, but if the price goes to the regular fare, it will cost $649 and that is $149 more than I have now," she said.

The actual amount of the winter fares -- and the extra charges that might be tacked onto them -- vary, depending on the carrier and the carrier's fare structure. For example:

*British Airways, Pan Am and TWA have been selling roundtrip tickets for winter travel for $418 for those traveling during the week between Washington and London; the replacement fare for that would be $609, a difference of $191. The weekend winter rate for that route was $468; it would increase to $649, a difference of $181.

*World Airways has been selling instant purchase roundtrip tickets for winter travel between Baltimore-Washington Airport and London for $318; the regular fare is $599, a difference of $281.

While other major airlines halted sale of low-fare tickets Thursday, in keeping with British orders, World Airways still was selling its $318 ticket yesterday on the premise that it had never been formally instructed to stop sales. "The British must notify the U.S. government, which in turn notifies us," said spokesman Michael Henderson, "and we haven't been notified by the U.S." He also said that World has taken the position that all passengers will travel for the price they pay for their tickets.

Two carriers were not affected by the British order: Peoples Express, a U.S. company, and Virgin Atlantic, a British firm. The winter rate for the Peoples Express roundtrip ticket for weekend travel between Washington and London is $376. Virgin Atlantic winter fares were not immediately available.