For exasperation at the airport, nothing beats the cancellation of your flight.

Whether the news pops up on the computer screen, is announced from the check-in desk or merely seeps out like a bad rumor, it induces a combination of fury and despair.How will we get where we are going?

When will we get there?

Does someone else fly there?

Who?

How far away is the counter?

Can our ticket be endorsed over to another line?

Why did the airline do this?

Weather and mechanical problems are often the reasons given, and when most passengers calm down, they have no argument.

But a surge of cancellations in January and February, when planes were flying almost empty, led many travelers, travel agents and corporate travel managers to conclude that airlines were canceling or combining flights to cut their losses.

The evidence that this was so is anecdotal.

Christopher J. Witkowsky, executive director of the Aviation Consumer Action Project, a Ralph Nader program in Washington, said that many of the passengers who called or wrote his organization at the time of the Persian Gulf war reported that airline employees, under persistent questioning, told them that flights were being canceled and combined as economy measures in bad times.

Sometimes no official reason was given to passengers, sometimes mechanical difficulties were cited, other times lack of personnel, rules requiring layovers for the staff or weather problems up the line. The impact of the war was also often cited.

The ongoing transfer of London routes from one airline to another is also creating cancellations.

A physician holding a round-trip ticket for a business trip to London on Pan Am this month found himself out in the cold when the route shifted to United, but United was operating only one flight a day, down from Pan Am's three.

Pan Am offered him a refund for his extra-cheap ticket, but by then he could not buy another ticket at the same low price.

Across-the-board cancellation figures are hard to get.

Each month all United States airlines report the number of flights canceled for mechanical reasons to the Federal Aviation Administration; other cancellations are reported, flight by flight, by the Department of Transportation, which does not compile these figures and would not consent to extract them from their computer records for this column.

But delays and cancellations caused by mechanical problems are said to total 5 percent of scheduled flights.

Taking 5 percent of the 18,000 daily flights by United States airlines from United States airports would mean that 900 flights a day are delayed or canceled for mechanical problems.

As airline fleets age and airlines operate under bankruptcy court protection, that figure is likely to edge up.

Until the end of 1989, the Department of Transportation kept a total of completed scheduled miles; that year, the figure was 97.1 percent. From this, you could presume that the figure for all sorts of cancellations would be 2.9 percent of scheduled miles.

This information is no longer collected, so it is not possible to determine what kind of a rise in cancellations, as opposed to delays, occurred during the gulf war.

The Department of Transportation publishes the monthly Air Travel Consumer Report, compiling totals on luggage mishandlings, overbooking problems and flight delays, and numbers of consumer complaints. The report lumps nonmechanical cancellation figures under total flight delays. Hoyte B. Decker Jr., the department's assistant director for consumer affairs, said breaking out the cancellation total had been discussed, but never decided on.

The only window on cancellations, a small, murky one, is under "flight problems," in the part of the report that covers consumer complaints. There are three subheadings: delays, cancellations and misconnections. For February, 82 people are recorded as complaining about cancellations; the February 1990 number was 129.

The ugly nub of the cancellation problem is contained in the statement that opens a section of the Department of Transportation leaflet "Fly-Rights," which is reiterated by Decker, and the airlines: "Airlines do not guarantee their schedules."

Ironically, passengers who are bumped from flights are guaranteed better compensation than those whose flights are canceled. If your flight is canceled and you miss the wedding, the speech, the connection, the airline does not owe you a thing.

But if you are bumped involuntarily, the airline may be required to compensate you unless it can get you to your destination within a certain time.

This is surely why the complaint letters earlier this year are so angry.

A Washington couple going to Brussels on Jan. 25 to see a sister dance the lead in "The Nutcracker" said their Pan Am flight had been canceled and that their tickets, based on frequent-flier coupons, were converted to British Airways tickets only as far as London. They had to pay their way, $456 additional, from there.

A couple due to return from the Virgin Islands to Washington via Raleigh-Durham on American Airlines in early March spent three days making the six-hour trip because so many flights were cancelled or delayed.

Tim Smith, a spokesman for American, said that the line did not cancel flights for economic reasons, and that its total of cancellations for mechanical reasons or weather on a stormy day in April was 58, or 2.5 percent of 2,317 flights in the day.

But in December and January, a total of 6,400 American flights were canceled, according to Smith, an average of 108 a day. This was 70 percent higher than for the same two months the year before. The airline attributed this increase to a job action by the pilots, which is now over.

The experience of a New York graduate student and his wife who visited Morocco in January points up the advice of the Department of Transportation on the subject of cancellations: "Airlines almost always refuse to pay passengers for financial losses resulting from a delayed arrival."

The couple, traveling on $474 tickets from Council Travel, were to return from Casablanca on Jan. 27. They called the airline, TAP, 72 hours in advance to reconfirm but say they got no answer then or later.

At the airport, they learned that their flight, No. 736, had been canceled three days before. To catch up with a flight home from Lisbon in time for classes and job, they flew to Paris on Royal Air Maroc, spending $1,087 on tickets, hotel and taxis.

So far, they have had no luck in their claim for a refund of this amount. After the couple insisted that no one answered the phone any time they called, Gloria Melo, a spokeswoman for the airline, said that it would reopen the case.

The only real hope for a passenger in a hurry whose flight is canceled is to try to get the airline to transfer the ticket to a line that has an appropriate flight. Many very cheap tickets, and tickets given in return for something other than money, are marked "unendorsable," meaning not transferable.

Two publications that provide information for airline passengers are: the 1989 edition of "Facts and Advice for Airline Passengers," published by the Aviation Consumer Action Project ($2 from the project, Box 19029, Washington, D.C. 20036) and the "Fly-Rights" pamphlet (item 146X), issued by the Department of Transportation and printed in 1985 ($1 from the Consumer Information Center, Pueblo, Colo. 81009).

On April 8, the European Community put into effect a rule with safeguards for passengers who are bumped from flights because of overbooking. Travelers taking flights out of European Community countries will get protection roughly equivalent to that offered in the United States.

The new rule applies to all scheduled flights - but not charter flights - leaving airports in the 12 Community nations.

If there are not enough volunteers to switch flights, the rule applies as follows: A passenger who is at the airport on time by the airline's definition, but cannot get aboard has three options: a refund, a rerouting or a later flight.

In addition, the rule says, the bumped passenger must receive a payment based on the length of the flight: up to 3,500 kilometers, or 2,170 miles, the passenger gets 150 European currency units, or $189 at present, and over 3,500 kilometers, double that.

But this compensation is cut in half on a 3,500-kilometer flight if the airline gets the passenger to the destination no more than two hours late; or on a longer flight, no more than four hours late.