WHEN Peter J. Sheldon boards a plane to any destination, his safety routine extends well beyond buckling his seat belt and noting the nearest exit. Once at his seat, he meticulously wipes down the cushions, armrests and tray table with disinfectant wipes. He refuses to touch the in-flight magazines and avoids using the restroom if at all possible. Since he began his in-flight cleansing routine he says he has weathered countless stares from other passengers but has never gotten ill from a flight.

“I’ve become a cautious germ freak,” said Mr. Sheldon, an executive at a commercial cleaning company. As someone who thinks about germs for a living, Mr. Sheldon may be more neurotic than most, yet a look at the growing number of products catering to traveling germaphobes suggests he’s not alone.

A combination of factors, including the H1N1 flare-up of 2009, recent bedbug infestations at hotels and increasingly crowded flights that put passengers in closer proximity to one another, has made people more concerned about the germs and bugs they can pick up while traveling. It has also made them more proactive about protecting themselves. As a result, companies are hawking a growing array of products promising to help, including disposable face masks, antiseptic spritzers, airline seat covers and portable air purifiers.

Magellan’s, a company that specializes in travel products, features a two-page spread on “travel health and hygiene helpers” in its spring catalog, including the Nano UV Scanner ($90), which, according to the catalog, uses ultraviolet light to kill germs on airplane tray tables, hotel bedding and TV remote controls. It is also selling Flight Spray, a “natural antiseptic” made with turmeric root that “helps prevent viral infections by creating an unsuitable environment for inhaled germs to reproduce” ($15.85). The health and hygiene category has increased 18 percent since 2006, the company says. Among the new offerings this year: a range of bed bug protectors, including organic sprays that are said to kill the critters, and luggage covers.

“Travelers hunker down to see who their neighbors are and are paranoid that they are flying in a sealed infections hospital ward,” said Stanley Weinberg, chief executive of Los Angeles-based Wein Products, which makes a small air filter that hangs around your neck called the Ultra-Mini Air Supply (about $135), which the company says uses ionic technology to reduce pollutants in the air. “Our Air Supply revenue has doubled over the past three years because of infection concerns,” he added.

Concerns among passengers that using such products might brand them as over-the-top neurotics seem to be diminishing, at least according to Angela Aaron, a fashion stylist who created and sells cover slips that fit over airplane seats to reduce exposure to germs. “In the beginning, people thought that you’d have to be phobic to use this product,” she said, but added that interest from both travelers and airline employees alike have encouraged her. “It’s airline stewards and stewardesses who are the most emphatic about what a valid idea they think it is,” Ms. Aaron said.

Although no data exists to suggest that more passengers are getting sick on planes than in the past, the Centers for Disease Control and Prevention points out on its Web site that “as with other close contact environments, cramped aircraft quarters may facilitate the transmission of influenza virus from person to person or through contact with contaminated surfaces.” And at least one study confirms the obvious: there are germs on planes.

In 2007, Charles P. Gerba, a professor of environmental microbiology at the University of Arizona, swabbed airplane bathrooms and tray tables on eight flights to see what bugs might be lurking onboard. Four out of six tray tables tested positive for the superbug methicillin-resistant Staphylococcus aureus (MRSA), and norovirus, the highly contagious group of viruses that can cause a miserable one- or two-day bout of vomiting, diarrhea and cramping, was found on one tray. Most of the bathrooms he swabbed had E. coli bacteria. Thirty percent of sinks, flush handles and faucet handles had E. coli, as did 20 percent of toilet seats, according to his research.

AIRLINES insist that they work diligently to keep aircraft clean. American Airlines deep-cleans its planes every 30 days on average, washing seat covers and carpets and scrubbing lavatories, bins and tray tables. Southwest introduced a new cleaning regime this year in which it performs a “light” deep-cleanse twice a week and a heavy cleanse each month “where all surfaces, nooks and crannies are thoroughly scrubbed and cleaned,” according to Chris Mainz, a spokesman.

And though many people worry about air quality in planes, it is the shared surfaces touched by passengers throughout the day that often transmit germs. “Cold and flu viruses can survive up to 72 hours on plastic surfaces,” said Dr. Gerba, while noroviruses can survive for two to four weeks.

But germ experts told about these new products say that many of the offerings may be more effective at subduing psychological fears than in preventing infection. “All you have to do is wash your hands prior to touching your face and also before you eat or drink anything,” said Philip M. Tierno Jr., the director of clinical microbiology and immunology at N.Y.U. Langone Medical Center and the author of “The Secret Life of Germs.” Liberal use of hand sanitizers or disinfectant wipes can also help ward off disease, he said. But other than surgical face masks, which he said might offer some protection against catching a cold from a hacking seatmate, he dismissed most of the products being marketed to travelers as “ineffective” or “inefficient.” For instance, while purifying the air with ions can help reduce airborne pollutants, he said, it can’t protect you from catching a cold. “All the passenger next to you has to do is sneeze, and you’re done,” he said.

Mr. Weinberg of Wein Products, agreed that fliers seated next to a sick passenger are more apt to catch a cold, but countered, “If you can reduce the number of germ particles that reach you, you reduce the probability of inhaling an infective dose.”

Then there are customers like Susan O’Neal, from Scottsdale, Ariz., who travels frequently for philanthropic projects. She said that the Wein Products Ultra-Mini Air Supply has kept her from getting sick on flights to more than 68 countries. The quiet hum of the battery-operated air filter, which she hangs around her neck when she boards, “makes me feel I’m safe,” she said.

Bottom line: Buying products that make you feel safer and wiping down the airline tray tables and hotel TV remote controls can’t hurt, but they should not be a substitute for diligent hand washing and use of hand sanitizers, which are the best ways to ward off infection.