Airlines, hotels and other members of the travel industry are increasing their efforts to ease travel for the handicapped. There have been several new developments around the country in recent months, and other actions are either under way or in the planning, including:

*World Airways has equipped all of its DC-10s with new collapsible wheelchairs designed to permit disabled passengers to move about the cabin and go to the lavatory unassisted. It is now completing modification of the planes to include seats with movable armrests -- for easier entrance and exit by wheelchair users -- and installation of "grab bars" in the lavatories.

World, as part of a two-year program aimed at providing "access to the skies" for all passengers, instituted a system-wide training program to educate its personnel on the needs of the handicapped traveler. All its planes have inflight briefing booklets printed in Braille; its DC-10s also have captioned briefing videotapes for the deaf and hearing-impaired, and studies are being conducted on the feasibility of modifying its other planes.

Dr. Harold Snider, executive director of the Society for the Advancement of Travel for the Handicapped, has called the airline one of the leaders in the field of transportation for the handicapped.

SATH is a 9-year-old, nonprofit organization with 3,000 members in the United States and about 20 other countries, including the principal travel agents and tour operators who deal with handicapped travel. Snider also is president of Access for the Handicapped, a Washington consulting organization whose work ranges from architectural access studies to training airline and hotel personnel to aid handicapped passengers and guests.

World has set up a Special Services Desk to help disabled passengers plan trips, including advice on such subsidiary services as barrier-free hotels and buses equipped with wheelchair lifts. (Snider, who is blind, points out that it's very difficult for an unaccompanied handicapped person to take a regular city tour bus in most major American cities. "The guides haven't been trained to work with handicapped persons, and most sightseeing buses are not equipped with wheelchair lifts," he says.)

*British Airways also has introduced a collapsible wheelchair with a removable armrest and back. The 15-inch-wide chairs are now on board all its long-haul 747 and TriStar aircraft on intercontinental routes.

*United Airlines is currently installing movable armrests in the first row of seats in each section of its entire fleet of 320 planes. The work is being done as each plane undergoes its major overhaul at the airline's San Francisco facility.

In 1982, United introduced its pioneering fleet of transcontinental 767s, each equipped with collapsible wheelchairs, movable armrests and two coach lavatories that could be joined together by specially designed doors to provide additional space when a handicapped person needed assistance.

*The American Hotel & Motel Association's executive engineers committee has launched a three-part program to improve hotel facilities for guests who are handicapped or elderly.

The AH & MA, which represents more than half of the available hotel and motel rooms in the United States, will set standards for new hotels, establish an evaluation process for existing hotels to see what can be done within budget limitations and offer educational programs for staffs that can be implemented in hotels and motels around the nation. The association will invite handicapped travelers to evaluate plans and look at renovations to make sure they fit their needs.

Virtually every chain hotel in this country offers special services for the handicapped, says AH & MA. All the major chains now have Telecommunication Devices for the Deaf; many have closed-caption TV and wheelchair access.

*Holiday Inns Inc. has announced the development of a visual alert system to alert the deaf or hard-of-hearing guest to a smoke alarm, a door knock or a telephone ringing. Installation of the device in all the 800 company-owned, managed or franchised hotels is expected to be completed by the end of this year.

The electronic system, which the American Hotel & Motel Association says is the first of its kind in the industry, uses a sound-activated receiver housed in a small portable box. A strobe light flashes, illuminating one of a series of red lights, to indicate which alert function has been activated. There is no charge to guests for use of the system.

*The American Automobile Association has published its newly revised "Handicapped Driver's Mobility Guide" that helps drivers find the adaptive motoring equipment they need. The AAA also is working on new ways to make driving easier and safer for the handicapped.

Tom Luce, who heads the American Automobile Association's handicapped driver research program, says, "We've just started to scratch the surface." A former racing car driver and retired Presbyterian minister, Luce worked as an automobile test driver for the AAA before he learned he had multiple sclerosis.

Luce continues to test cars for the AAA -- vehicles that have been modified with special equipment for motorists with physical disabilities. Depending on the severity of the driver's impairment, modifications may range from a simple pedal extension to a control package of hand levers on the steering column, designed for the driver whose legs cannot be used to accelerate or brake. Hydraulic systems can provide power braking and steering for persons suffering from weakened muscles. (Modified cars also are tested by a non-handicapped driver to insure that the changes do not create problems for them.)

Other potential refinements that are being studied, according to Luce, include: voice-activated controls to operate lights, windshield wipers, air conditioners and heaters; wheelchair carriers built into door panels and the installation of cellular phones in vehicles to provide more security. General Motors is about to begin marketing its own adaptive hand-control system -- the first time an automobile manufacturer has offered its own factory-installed equipment.

Luce says that while at least an estimated 500,000 North American drivers "have significant mobility handicaps" due to accidents or illnesses like muscular dystrophy and multiple sclerosis, our aging population presents a much broader problem. Perhaps a million-and-a-half drivers are suffering from handicaps "with a small 'H' " -- hearing loss, limited vision, arthritis, weak muscles -- and the ongoing research at most major automobile manufacturers should help them.

The Mobility Guide gives advice on selecting vehicles and equipment, maintenance and installation, and includes a directory of organizations and firms in the United States and Canada that offer products or services for handicapped motorists.

*The Society for the Advancement of Travel for the Handicapped has revised its brochure titled "The United States Welcomes Handicapped Visitors," which it produced as an aid in planning vacations in North America.

The brochure, written by Snider under a contract to SATH, was a joint project of the U.S. Travel and Tourism Administration, Greyhound Bus Lines and the American Society of Travel Agents. It details what facilities for the handicapped to expect on U.S. planes, trains and buses and lists hotel chains with accessible rooms.

The brochure is free to the public -- send a No. 10 self-addressed envelope with 39 cents postage; the material also is available free on cassette tape and in Braille. Write to the society at 5014 42nd St. NW, Washington, D.C. 20016 (966-3900).

*Some travel agencies have concentrated on serving the handicapped and design group packages with their needs and limitations in mind, and they are becoming increasingly sophisticated in their services. These operators have become especially knowledgeable about such matters as airline capabilities in dealing with the disabled, hotels that have reduced architectural barriers and provided additional safety features, rental car companies that offer vehicles with adaptive equipment and cruise ships with, for example, elevators between decks and cabin doorways and bathrooms large enough for wheelchairs.

Finding rental cars equipped with special systems can sometimes be a problem. Though major agencies like Hertz, Avis and National offer such cars, they may not always be available in every U.S. town, and dropoff in a different city may not be permitted. Overseas, the handicapped driver faces more complications and less availability.

Alexandria Travel Services Inc. is a small agency in Alexandria that has begun to handle travel arrangements for the handicapped (as a sideline to its regular travel business) because, as manager Jean Boehlert says, it's "something I want to do." To save her clients money, she looks for a resort hotel that has facilities for the handicapped, and then she puts the clients on a lower-cost package tour using that hotel.

Among U.S. agencies specializing in travel by the handicapped are: Centers for the Handicapped Inc., 10501 New Hampshire Ave., Silver Spring, Md. 20903, (301) 445-3350; Flying Wheels Travel, P.O. Box 382, Owatonna, Minn. 55060, (800) 533-0363; Wings on Wheels, Evergreen Travel Service, 19505 (L) 44th Ave. West, Lynnwood, Wash. 98036, (206) 776-1184; Wheelchair Wagon Tours, P.O. Box 1270, Kissimmee, Fla. 32741, (305) 846-7175; Whole Person Tours, 137 W. 32nd St., Bayonne, N.J. 07002, (201) 858-3400.