FREE guidebooks from the friendly skies? Though air passengers who've read them know that commercial travel book publishers don't have to worry much about that kind of "competition," some airlines offer useful publications for the tourist and businessman just for the asking.

Foreign carriers are particularly prolific with free publications, despite the fact that serious economic problems have caused a number of lines here and abroad to tighten operations to help cut costs.

The International Air Transport Association reports that last year its 117 member airlines suffered operating losses totaling $250 million, before interest and taxes -- but most foreign flag companies are either government owned or heavily subsidized. Some also act as distributors for publications produced and paid for by their well-funded government tourist offices, which spend millions to attract tourists and the currency they bring.

Top honors for quality material in our informal (not all-inclusive) survey go to Swissair. One of that airline's most popular booklets is titled, "Public Holidays Around the World," which is dedicated "to the traveling businessman" and covers about 160 countries in 86 pages. Another is a 71-page booklet, "China Mini Address and Telephone Directory." It includes what Swissair describes as "all the telephone numbers you are likely to need" in Peking, Canton and Shanghai, as well as important numbers in provincial cities. Because addresses are also in Chinese characters, the airline adds, it is easier to communicate with hotel staff and taxi-drivers.

And while its small guide to kosher hotels and restaurants in Europe may sustain some travelers "spiritually as well as physically;" and its full-color, 264-page paperback guide to "all the hotels Swissair can book for you as directly as it does your flight" is an interesting world tour of accommodations even if you stay home, special mention should go to a series obviously aimed at the high-flying business official.

Titled "Executive Guides," these are highly-informative folders with much of what the business traveler needs to know about Eastern Europe, the Far East, the Middle East, Africa and South America. Covering dozens of countries, they include current, condensed facts on subjects like population, currency, transportation, accommodations, tipping, climate and clothing, etc. (Swissair, incidentally, has just announced it is serving free alcoholic beverages on all its international flights in all classes -- which may make their literature even more readable.)

Write to Swissair, 1717 K St. NW, Washington,D.C. 20006.

Close behind Swissair are KLM Royal Dutch Airlines, Lufthansa German Airlines, SAS Scandinavian Airlines and British Airways .

KLM offers a number of publications, including a 192-page guide, "KLM's Holland;" a 304-page hotel guide, "Golden Tulip Hotels" (both paperbacks); three pamphlets, "Budget Travel Tips," "KLM's Europe by Car and Train," and "Business Travel Guide to the Arab World;" and a pocket-size booklet, "Holland," with handy facts for travelers.

Write KLM Royal Dutch Airlines, 1825 K St.NW., Suite 501, Washington,D.C. 20006.

Lufthansa distributes its government's Press and Information Office edition of an 83-page paperback book, "Facts About Germany," which discusses the country's history, politics, economics, education, science and other topics; two paperback calendars of events: the 166-page "Folklore Sports Cultural Events" and the 62-page "Trade Fairs and Exhibitions;" a colorful magazine, "Happy Days in Germany," and a series of small booklets titled "A Business Guide to getting around overseas" and covering Europe, Near East and Africa, Pacific and Far East.

Write Lufthansa German Airlines, 1640 Hempstead Turnpike, East Meadow, N.Y., 11554.

SAS publishes a series of "City Portrait" pamphlets on 58 cities ranging from Bergen to Rome, which are easy-to-carry short guides; two other pamphlets, "Afforable Scandinavia 82" and "Scandinavian Workshops, Problem Solving for the Society of Today," and its "Exercise in the Chair" folder designed to help passengers limber up in flight.

Write SAS Scandinavian Airlines, 13802 Queens Blvd., Jamaica, N.Y., 11435, Attn. Box A.U.

British Airways offers a 32-page pamphlet titled,"Weather Wise," a mini-weather report on many cities around the world; a series of 20-to-30-page pamphlet guides to a variety of countries; a leaflet, "The London Connection," on transportation between London airports and downtown, and maps of London and the United Kingdom. Among other items, the airline also distributes "Britain for all Seasons," a 41-page pamphlet guide, and large-format brochure/maps on major areas of Britain, both of which are prepared by the British Travel Authority.

Write to John Lampl, British Airways Public Relations, 245 Park Ave., New York, N.Y. 10167.

Meanwhile here at home, U.S. airlines are emphasizing, as one official put it, standard "quality brochures aimed at explaining services to the clients -- tour booklets and promotional material designed to make the dollar go further."

They are not, as a rule, giving away other publications -- in fact, most domestic airlines stopped producing this type of material years before the current economic crunch. A Pan American Airways spokesman, who confirmed that the carrier now has no regular free publications, noted that "Pan Am's USA Guide" and "Pan Am's World Guide," published by McGraw-Hill, are regularly revised and sold in bookstores.

Delta Air Lines, official carrier for the Knoxville World's Fair, offers a free "Lodging Guide to Atlanta," world's fair edition, which does not even mention Delta. (The line's headquarters is in Atlanta.) The 57-page pamphlet is available from Delta Air Lines Inc., 1777 N. Kent St., Suite 707, Arlington, Va. 22209.

Despite some continuing criticisms about official housing services and prices, and the quality of some exhibits, the 1982 World's Fair greeted its sixth millionth visitor at Knoxville last month to set a new record by already topping final attendance figures at the 1939 New York World's Fair, the 1962 Seattle Fair, and the 1974 Spokane Fair. Management said happily the attraction was "surpassing our wildest hopes."

Visitors who intend to book package tours to the show should consult operators they have dealt with in the past or whose reputation indicates they will stand behind their product. If you're going without a package, it's a good idea to check individual room rates in advance at the property where you plan to stay and then make your reservations directly with the hotel or motel before heading for Tennessee. The Fair runs through Oct. 31 -- Fall should bring cooler weather and less crowds.The Nonsmokers' Travel Club of GASP (Group Against Smokers' Pollution), with headquarters at 8928 Bradmoor Dr., Bethesda, Md. 20817, now has 1400 members who try to plan their travel to avoid having to breathe someone else's cigarette, cigar or pipe smoke.

A national, non-profit organization, it seeks to enforce the rights of nonsmokers on public transportation and informs members of travel facilities and trips for nonsmokers. The Club is currently sponsoring two trips: a Sept. 18-Oct. 3 tour of England, Ireland, Scotland and Wales with flight to London via TWA ("entire nonsmoking cabin") and "smoke-free" tour bus (nonsmoking driver and guide); and an Oct. 19-23 World's Fair bus trip from Washington, again with no smoking.

Reservation deadline for the London flight is Aug. 28; for the Knoxville trip, Sept. 11 -- provided space is available. Information at 530-1664.