ARGAIN-hunting tourists have joined the "Air Charter Revolution." Tense battles are being fought as airlines brandish new fare weapons or hurl charges of subversion into the jet stream to the victors will go a major share of that highly prized stabilizer: the U.S. traveler's dollar.

Meanwhile, tour packages and their sometimes confusing [WORD ILLEGIBLE] continue to multiply like bees on honey. A few tricky operators are still around, and you can still get stung.

But regardless of whether the scheduled or supplemental (charter) airlines wind up "winning" - and it's not certain that, in the long run, either must suffer criticial losses provided both government and industry make the right decisions - the tourist stands to save money.

That's a victory for the battered consumer, who has sampled the sweet taste of low-cost air travel and clearly demands more.

If you don't know what all the shouting's about, just one glance at the following figure will provide an eye-opening comparison. Typical roundtrip rate in dollars this summer for scheduled flights between Washington and London: First class, $1,393; economy, $829 (tentative); 14/21-day excursion, $676; 22/45-day excursion, $632; 22/45 APEX, $476; youth fare (12-21 years), $588. (Plus, to APEX and excursion fares add a $30 weekend surcharge.)

Cost of a typical round-trip, 15-day ABC charter flight departing for London on a weekend this June: $359 (even less off-season).

On this page, and elsewhere in this International special travel section, we offer information to help you understand more about the complex and changing charter picture. There is no substitute, of course, for a good travel agent. But a knowledge of the basics will save you time and perhaps cash.

Consider, first, these developments:

Cheap packages such as OTCs (with land arrangements) and overseas destinations are being offered by various tour operators - in some cases using jet aircraft chartered from regular scheduled airlines, whose names may even appear on the brochures (see chart explaining terms on Page H4). Scheduled airlines are forbidden by the Civil Aeronautics Board (CAB) from marketing ABCs or other charter tours directly to consumers, though they may take part in charter programs in conjunction with tour wholesalers/operators.

Scheduled U.S. airlines, citing rising fuel and labor costs, have sought regular fare increase to bolster sagging profits or attack outright deficts. They point to figures which they maintain show their fares to be good buys when compared to sharp price increases in other fields. At the same time, they are facing both the charter revolution and government moves to "deregulate" the scheduled carriers to increase competition between them. The airlines see both developments affecting their stability and even threatening their ability to exist.

(Scheduled airlines came into being because of the vast distances in this country and the need for fast, regular, dependable transportation on a fixed of business. Planes must fly regardless of load factor - number of seats sold - and often take off half-empty. Unscheduled airlines - also known as supplementals or charter lines - do not fly regular routes and can offer reduced rates because charter operators are permitted to cancel flights unless they have an economically feasible passenger load - usually 100 per cent.)

American Airlines last week was awaiting a CAB ruling (expected by next Thursday) on its proposed "Super-Saver" round-trip transcontinental discount fare between New York/Neward and the West Coast. If approved, cost for the peak summer season would be $227 Tuesday through Thursdays, $247 on Mondays and Fridays, and $268 on weekends. (Comparable regular round-trip fare, Washington-Los Angeles, is $384.) American says its proposal shows that competition does exist.

TWA and United Air Lines also have filed a similar plan with the CAB to remain competitive on the route, though both opposed certain aspects of the American plan. TWA believes it would result in loss of income rather than stimulate business - they prefer to see the fare reduced in the off-season (fall and winter). United "contends that Amercian's proposal is uneconomical, its ticketing requirements do a disservice to the passengers and the discounts will be injurious to various charter experiments such as the Advanced Booking Charters."

A proposal by World Airways, a charter carrier, to provide scheduled coast-to-coast flights for about $89 one way is under consideration by the CAB. If approved, World would fly between Baltimore-Washington International Airport and airports near Los Angeles and San Francisco.

Another controversial decision, whether to permit Britains's Freddie Laker of Laker Airways to begin his barebones (no reservations; no meals; first-come, first-served) "Skytrain" jet service once daily between London and New York, will also face the CAB soon, having won a court victory in London. Round-trip fare was projected at $230, but it will probably increase about $50.

With a minimum 30-day advance purchase requirement but no cancellation penalty, and a provision to use up to 35 per cent of seats on regularly scheduled flights, Amercian's new fare is seen by some charter operators as an effort to take over their charter market. And they wonder what will happen to these prices - and similar discount or promotional fares - if the spur of low-cost charters disappears.

Some are bitter because they made long-term commitments (including chartering aircraft from American Airlines) and were beginning to market their ABC tour packages.A spokesman for the supplemental air carriers pointed to the situation in 1969-70, "when charters had become predominant" on the West Coast-Hawaii route. Then United moved in "with its wellknow name, cut its fares and took over the market."

United, in reply, explains that in 1969 it "developed a new pricing concept called Group Inclusive Tours (GII)," which included airfare and a ground package requiring groups of 154 passengers and 30-day advance purchase. The airline "was able to lower the airfare because of the economics of the group package . . ." and points out it was "not a newcomer to that route." On May 1, United will celebrate the 30th anniversary of its service to Hawaii.

Randall Malin, American Airline's vice president for passenger sales and revealing comments in answer to criticism of his Super-Saver fares from charter operators. His statements, made during an interview with a trade publication, were confirmed last week by an airline spokesman.

"I am sympathetic with their (charter operators') viewpoint . . . but they are taking our business from us and we cannot acquiesce in that and continually accomodate them on charters," Malin said.

"The CAB has been creating de factor deregulation, reacting to political and consumer pressure by making charters more and more available, and then each time it says, 'If this one doesn't work, we'll make it even more liberal next year.' But they preclude us from directly selling ABCs and that is unfair.

"There is no problem with the charter theory; it takes no genius to see you can make more money by flying at 100-per cent load factor rather than 50-per-cent. The problem arises, first, in that scheduled serivce will suffer eventually with more and more business going into charters. We would have to reduce scheduled service . . .

"The second problem is that while charters are serving people in markets like New York to Los Angeles and San Francisco, they are not providing this low-cost service to people in places like Des Moines, Dayton, Sacramento and Little Rock," Malin continued.

American Airlines feels - and their suggestion is not new - that the discretionary (vacation) and the business traveler should be combined on the same plane, thus offering low-cost fares on scheduled service. However, ". . . there must be some restrictions," Malin said, "such as advance booking and the requirement that no more than 35 per cent of the plane" be assigned to the reduced fare to avoid "diluting your regular fares."

The part-charter also has an energy conservation angle. But the idea of some passengers paying higher fares (primarily for freedom from restrictions) and thus subsidizing other passengers paying discount fares for seats on the same plane is considered unfair by many - though similar practices are already in effect with "excursions" and other special fares.

The supplemental carriers, aside from their fears about being shoved out of the market entirely by temporary promotional and discount fares (after substantial investments and showing the way), make these two main claims:

First, scheduled air carriers will not really lower regular air fares unless forced to: second, charters can tap a new market by attracting millions of Americans who otherwise would not fly.

Other critics charge that some scheduled routes are oversaturated, making it impossible for any one carrier to fly them economically, and that the elimination of marginal competitive frills (special meals, free drinks and gimmicks) would help reduce fares further.

The Carter administration is seeking to convince Congress that it should reduce federal regulation of the airline industry so the scheduled lines will have to compete more in fares rather than in service frills. Rules would prevent "predatory, below-cost pricing" and protect small communities against the loss of service.

And then there's the airlines overbooking controversy, and the hassle over whether to ban all smoking on airplanes, two other conflicts the CAB must soon resolve. Not to mention the continuing Federal Trade Commission investigation of travel industry practices.

However, no need to wait for all the regulatory decisions and answers. If you're planning a charter trip now, just read the fine print and remember:

Charters may be canceled by the operator for a number of reasons - better know his track record or get an agent. If you may be penalized, so consider insurance.

To get the lowest price, you must book in advance; be very flexible (departure dates are limited and may be changed, and the airport may not be the one most convenient to you); accept the fact that the plane most likely will be jam-packed, and be prepared for possible takeoff delays in one or both directors.

Operators work on very low profit margins and the competition is intense, which has good and bad points. As the list of charter flights grows, your chances of finding the right one to the right destination at the right time for the right price continue to increase.

Charters certainly may not be for everyone, but millions have enjoyed them - and the cost of a ticket indicates their skies are friendly indeed.

Rosenberg is Travel Editor of The Washington Post