If you have no fear of flying, air travel is quite uninvolved. You buy a ticket, get to the airport in time for boarding, pass security inspections, check in at the flight gate, hop on the plane and take off. Right?

Not always. A small percentage of those who travel by air have found their tickets to be totally useless in getting them on their desired flight.

They are victims of overbooking, a widespread industry practice under which airlines sell "confirmed reservations" on a flight to more customers than there are seats.

When they learn their flight has been oversold, and realize that planning ahead, making the reservation, picking up the ticket and getting to the airport on time doesn't mean they'll get to fly away as planned, some customers have been seen holding their tickets in tightly-clenched fists, screaming "What do you mean there's no more room on my plane?"

People almost never are consoled by the airlines' explanation that they have to overbook flights to compensate for phantom air travelers who make reservations and don't show up, or books several flights and then take the one that turns out to be most convenient for them.

And rather than being honored when they are part of the small number that gets bumped from flights as a result of overbooking, they get angry.

At that point, they are probably past understanding the airlines' claim that overbooking is vital to the traveling public. As Trans World Airlines recently told the Civil Aeronautics Bureau. "If the current practice of overbooking by TWA were eliminated, some 505,000 passengers (in a 9-month period) would not have been able to travel on the flights they wanted - or at all." Even though about 7,800 people were denied boarding on its confirmed flights, TWA explained, those other 505,000 people "were accommodated on flights that were booked over the capacity of the aircraft."

The CAB is currently evaluating this and other comments from the public and airline industry on overbooking.

TWA noted that its no-show rate "is approximately 20 per cent." Without overlooking, they said, they would lose so much money that fares would have to be raised substantially for all passengers. "There's nothing as unsalable as an empty airline seat once the door has been locked and the flight is on its way," was TWA's lament.

But Andy Spielman, area director of the Ameican Society of Travel Agents and vice president of Waters Travel in Washington, says there are better ways to compensate for no-shows than overbooking flights. "The whole thing is totally unnecessary," he says. "If the airlines put a tighter control on their reservations department there wouldn't be any need."

Spielman says airlines should reinstitute a practice they tried and abandoned in the early '60s of penalizing those who don't keep their reservations. "What other business would operate in such a slap-happy position?" he asks. If the airlines required advance payment and then refused to refund even part of the money to customers who do not honor their confirmed reservations, they could avoid inconveniencing anyone, Spielman says.

As a travel agent, Spielman's lament is obvious. "It's a disaster from our standpoint," he says. And, he adds, it makes travel agents look terrible. "It's the old case of maybe the poor guy is not to blame but he's the only one I can holler at."

Clients have complained to Spielman about overbooking by airlines, hotels, car rental agencies and even steamship lines, he said. He talks of unlucky travelers who begin their vacations by getting bumped from an oversold flight, hanging around the airport, and finally arriving late and tired at a hotel which has given away their room and refuses to refund the room deposit. Though he admits the incidence of denied boarding is not large, Spielman says, "Even once is too much."

In 1975, out of 185,631,812 people who took domestic flights, 120,686 were denied boarding, according to figures given to the CAB by airlines. Of that number, CAB figures show only 56,220 people were eligible for denied-boarding compensation.

When airline overbooking leads to oversold flights, passengers who are denied boarding might get some satisfaction from a ruling made by the CAB in 1967.

If you are denied boarding, the airline must give immediate written notice that you might be eligible for denied-boarding compensation. Then, if the airline cannot get you to your destination on another flight within two hours of the time you originally were scheduled to arrive (or four hours in the case of international flights), you must be reimbursed up to $200 for your ticket on "the day and place the denied boarding occurs," according to the CAB. You can also keep your ticket and use it at any time.

If your flight was oversold and you arrived more than two hours late on a non-stop flight that cost you $98, for example, you could get a refund for the whole thing and still use the ticket. In the case of a flight that is not non-stop, you are eligible for a refund for the leg of the flight which was oversold, according to the CAB. The CAB has either legitimized nor condemned airline overbooking.

If you are in danger of missing a connecting flight or can't wait for a check to be prepared for other reasons, the airline must sent it to you within 24 hours, according to the CAB.

A passenger does not have to accept the denied-boarding compensation, however. If it is accept, the airline is relieved of further legal responsibility, according to the CAB ruling. Passengers have the right, however, to think it over for up to 30 days before signing the check.

Consumer activist Ralph Nader was awarded $25,000 in punitive damages in 1972 after he was denied a seat on Allegheny Airlines from Washington to Hartford.

Chances of being denied boarding are relatively slim, according to airline reports filed with the CAB. But, according to a CAB report on denied-boarding compensation for 1974 and 1975, airlines are doing it more, not less.

"The certificated carriers regressed in their performance as measured by passengers denied confirmed space in domestic operations," the report said. In 1974, 5.8 passengers out of every 10,000 who boarded flights were denied boarding. In 1975, 7 out of every 10,000 passengers who boarded flights got bumped.

"In actual numbers, 120,686 passengers in 1975 were denied confirmed space vs. 100,990 in 1974," the report said. The number of people who took domestic scheduled flights decreased about 260,000 during the same time period, from 173.63 million to 173.37 million, according to CAB reports.

The highest incidence of oversold flights occurred during the holidays. In December, 1975, the industry denied-boarding rate reached 10.8 per 10,000 enplanements.

The accompanying chart, compiled from CAB figures shows the over-booking record of domestic airlines in 1975.

Sauve is a news aide and a regular contributor in the Weekly section of The Washington Post.

The following chart, complied from Civil Aeronautics figures, shows performance of domestic airlines in connection with overbooking in 1975.(TABLE) *2*Number of passengers(COLUMN)Passengers eligible(COLUMN)Total Denied confirmed space(COLUMN)for Denied Board-(COLUMN)number(COLUMN)per 10,000 enplanements ing Compensation(COLUMN)carried Aloho(COLUMN)59.6(COLUMN)608(COLUMN)2,025,315 Hawaiian(COLUMN)26.6(COLUMN)119(COLUMN)2,741,552 Pan American(COLUMN)20.9(COLUMN)544(COLUMN)896,186 Western(COLUMN)14.9(COLUMN)5,032(COLUMN)7,768,508 Frontier(COLUMN)10.4(COLUMN)2,313(COLUMN)3,732,619 American(COLUMN)8.7(COLUMN)8,716(COLUMN)19,043,666 Trans World(COLUMN)8.2(COLUMN)6,383(COLUMN)13,848,511 Continental(COLUMN)7.6(COLUMN)3,423(COLUMN)7,058,970 Ozark(COLUMN)7.9(COLUMN)1,683(COLUMN)3,345,443 North Central(COLUMN)16.2(COLUMN)1,319(COLUMN)4,530,214 Delta(COLUMN)5.9(COLUMN)5,493(COLUMN)26,149,138 Air West(COLUMN)5.5(COLUMN)1,263(COLUMN)3,587,696 Southern(COLUMN)5.5(COLUMN)1,174(COLUMN)2,935,351 United(COLUMN)5.5(COLUMN)7,706(COLUMN)28,685,191 Texas Int'l(COLUMN)4.7(COLUMN)550(COLUMN)1,616,530 Allegheny(COLUMN)4.5(COLUMN)1,354(COLUMN)7,982,288 Braniff(COLUMN)3.6(COLUMN)1,635(COLUMN)7,791,871 National(COLUMN)3.3(COLUMN)650(COLUMN)4,170,729 Alaska(COLUMN)2.8(COLUMN)214(COLUMN)759,492 Piedmont(COLUMN)2.6(COLUMN)679(COLUMN)3,602,990 Air N.E.(COLUMN)2.3(COLUMN)72(COLUMN)408,719 Eastern(COLUMN)1.8(COLUMN)2,643(COLUMN)22,949,559 Wright(COLUMN)0.0(COLUMN)0(COLUMN)53,930 Aspen(COLUMN)0.0(COLUMN)0(COLUMN)114,154(END TABLE)