A Chicago area woman popped two tranquilizers into her mouth just before boarding a flight home from Seattle only to discover, after a terrifying takeoff and an aerial look at Mt. St. Helens, that they don't take effect immediately. However, she had a nice snooze going home in the car from O'Hare International Airport. Then there is the story of the corporate executive who lost both his wife and his job because he spent too much time on the road. The man was afraid to fly, so he spent most weekends traveling to and from business meetings by train. He was prematurely retired when a train on which he was returning from a Friday meeting in California was delayed and he missed a board of directors meeting Monday morning. Although they and most other "aviophobes" prefer to remain anonymous, fearing they would be ridiculed, many make no bones about their fear of flying. Such entertainers as Bob Newhart, Maureen Stapleton and Jackie Gleason are fearful flyers. Mamie Eisenhower didn't like flying. Neither do science fiction writers Ray Bradbury and Isaac Asimov. Although most airlines pay little attention to the problem, recent studies indicate that the fear of flying is far more serious than anyone imagined. one in every six adult Americans -- 25 million people -- is afraid to fly, according to a 1978 study by International Research Associates. A follow-up report by the Boeing Commercial Airplane Co. released this year estimates that the U.S. air travel industry loses $1.6 billion a year in revenue because aviophobes refuse to fly. Boeing is attempting to coordinate at a national level scores of unrelated studies of aviophobia as well as local programs geared to help individuals overcome their fears. The company held its first national seminar for experts on the subject in September. "Quite frankly, we're interested because studies have shown 25 million Americans are afraid to fly," said Dr. Kit Narodick, director of marketing communications analysis and support for Boeing. "If we get more people on airplanes, we sell more airplanes." Boeing is looking into the possibility of easing the fear of flying by changing the interior color schemes on airplanes and modifying the mandatory safety briefing delivered by flight attendants before takeoff.