How to get the best travel deal? Let your computer help plan your trip

Flying one-way from Chicago to Buffalo, N.Y., on a Thursday should be a simple matter. The major airlines with direct flights - American and United - charge $203. US Air is $10 cheaper, with a connection through Pittsburgh or Indianapolis.

But - with a little shopping around - those fares can be beaten. In fact, industry observers say, a lot of airline discounts are available to the careful traveler.

So, after a couple of hours of phone calls, I found a connection between two airlines through Toronto. The savings over the direct flights: $31.28.

Two hours of telephone work may seem too bothersome for those kinds of savings. Is there a better way?

Yes, say these airline observers, who note that air fares are as competitive as they have ever been.

One way is to get a good travel agent, says Ed Perkins, publisher of Economy Traveler, a bimonthly newsletter out of Menlo Park, Calif. A good agent will take the time to dig out the best deals, he says.

If a good travel agent isn't available, another way is through one of the emerging private electronic fare-and-schedule services, Mr. Perkins says.

The first such service to start up is apparently the OAG Electronic Edition of Official Airline Guides, a company of the Dun & Brad-street Corporation. The Oak Brook, Ill., company's printed airline fare and schedule guides have been widely used for years. A little over a year ago it introduced its computerized version.

Subscribers access the data banks with their own computers or terminals and can ask for flight information, based either on the best fare or best schedule for the traveler.

''For the first time, the traveler has access to all the fares and all the schedule information,'' says Nancy Meyer, marketing director of the company's electronic publishing arm. An average session lasts about seven minutes and costs $3, she adds. There's also a one-time subscription fee of $50.

Of the 13,500 or so direct subscribers - a total a little below the company's growth projections - most are concerned primarily with business travel. But the consumer can also use the system through videotex systems, such as CompuServe and the Source.

Mr. Perkins, for one, has tried the system and is impressed so far. He found an unrestricted round-trip flight between San Francisco and New York for $450 when the full coach rate was $938.

But at least one potential competitor is banking on consumers finding his system better.

''It'll be probably the most complete, versatile electronic data service of its kind,'' says Louis Van Leeuwen, president of Airfare Publishing Company in Riverside, Conn. The service, scheduled to start early next year, will list not only hotel and restaurant information but also such things as general location and price range. It will also be able to make reservations for subscribers.

Perkins says these new electronic services will be extremely helpful in an era when fares can change so rapidly. Business travelers stand to gain the most, since they usually can't fool with advance purchase, minimum stays, and other restrictions on discounted travel.

Just be careful about which airline you choose, cautions Daniel T. Smith, supervisor of consumer affairs at the International Airline Passengers Association. He says those with a questionable future may not refund for canceled flights. Mr. Smith suggests checking with a travel agent beforehand about the airline's refund policy.