As new cases of novel coronavirus are growing, the travel industry is feeling the impact -- with vacationers and business people debating whether or not to cancel or postpone trips, and some countries, including the U.S., implementing travel restrictions.

But airplanes are still flying, and travellers still travelling, albeit with extra bottles of hand sanitizer and disinfectant wipes in carry-ons.

Still, as you board the aircraft and sit in your seat, you might find yourself reconsidering inflight hygiene -- and wondering just how thoroughly the aircraft's actually been cleaned before you boarded.

CNN Travel spoke to airlines, airplane companies and medical experts to find out what's been done to ensure you're flying in as hygienic an environment as possible, and what passengers can do for extra reassurance.

Normal cleaning procedure

Christian Rooney is the manager of JetWash Aero, a specialist aviation cleaning company based in the U.K. that's tasked with turning around aircraft between flights.

Rooney tells CNN Travel that the cleaning process varies depending on the schedule of the aircraft in question.

When aircraft downtime is very limited, some of what Rooney calls the "very straightforward cleaning," such as removing old newspapers and passenger trash, will be done by the cabin crew at the end of the previous flight.

"A basic but more thorough cabin clean is usually carried out at night -- or when there is more downtime -- and it includes the cleaning of toilets, wiping down and disinfecting of trays, cleaning galleys, [overhead bins], seats etc. This may take up to an hour or longer," explains Rooney.

"An airline will also always schedule a 'deep interior clean' every month or six weeks. This clean takes several hours and is extremely thorough."

Cleaning products and disinfectants are approved by aircraft manufacturers, says Rooney.

"Some of the disinfectants we use are effective against a wide range of pathogens and are known to inactivate complex viruses with similar properties to SARS, E. coli, avian flu, MRSA etc," he adds.

These offer antimicrobial protection for up to 10 days, he says.

Stephanie Biron, a recently retired flight attendant who used to work for American Airlines, tells CNN Travel that, in her experience, standards of aircraft cleaning would vary.

"A lot of times you come on and it's not terribly satisfactory, but you have to rely on the individuals doing their jobs, because that's what they've been paid to do," she says.

"Sometimes you come on and you have to go out and tell the agent, 'look, the plane looks terrible. We need somebody to come on and redo it.' It just varies all the time. Sometimes you come on in the morning and they deep cleaned the whole thing, or at least they told you they have."

Passenger personal hygiene

Some airlines have requested additional measures due to the current climate, says Rooney.

"We have seen an uptick in the requirements and levels of disinfection, spraying and fumigation of the cabin, as the airlines look to address concerns over the coronavirus," he explains.

But Dr. William Schaffner, a professor of medicine in Vanderbilt University's division of infectious diseases, says that he doesn't think there's much more carriers can do to prevent the spread of coronavirus.

Because transmission most often occurs person to person, the inanimate environment of the airplane isn't really the problem, says Schaffner.

It's still wise, he says, to wipe down surfaces -- but ultimately it's handwashing that is the most important preventative step.

"Even if there is virus in the inanimate environment, it's not going to jump off the seat and bite you in the ankle. You've got to touch it, and then touch your nose or your mouth," Schaffner explains.

"So it's those hands we have that are the important intermediary -- and that's where I would put the emphasis. Use those wipes on your hands. That's the important thing."

Dr Paulo Alves, who is currently attending IATA's Aviation Resilience Health workshop in Singapore -- which is working to address the overall impact of COVID-19 -- agrees with Schaffner.

"The most effective, simple measure vacationers should implement is to wash hands frequently with soap and water. If soap and water are not available, hand sanitizer should be used," says Alves.

"It seems reasonable to wipe the tray table surface, where it is more likely for droplets to land after someone coughs or sneezes. Travelers should maintain good personal hygiene on board flights, before flights and after flights and avoid touching their face."

Travel medicine specialist Richard Dawood agrees, and says this advice stretches to navigating airports too. "Remain aware of where your hands have been," he says.

Former flight attendant Biron also expresses concern not just for passengers -- but for air crew. They're just as likely to get sick, she points out, or feel pressured to still fly while unwell.

Airlines for America, the aviation group that represents North American carriers, says airlines are working closely with federal authorities -- and tells CNN Travel that the safety and security of passengers and crew "is -- and always will be -- the top priority of US carriers."

"I really don't think [airlines] can do very much. They might make the wipes more available to individuals," says Schaffner.

Airline response

So what are airlines doing differently right now?

Brian Parrish, spokesman for Southwest Airlines, tells CNN Travel that Southwest aircraft undergo "regular cleanings between flights and a comprehensive cleaning when aircraft are parked overnight."

"Our cleaning program includes the disinfecting of all hard surfaces within the cabin, as well as seat and carpet cleaning," he says. "Southwest will continue to monitor and follow all guidance from the Centers for Disease Control and World Health Organization regarding the coronavirus and make any adjustments to our procedures, as necessary."

Curtis Blessing, an American Airlines spokesperson, echos Parrish.

"Our aircraft, including lavatories, are cleaned on a regular basis, and the depth of the cleaning varies depending on turn times and type of flying," he says. "Lavatories are cleaned, floors are spot cleaned and visible trash is removed from seat pockets on all flights."

Transcontinental, Hawaii and international flights see a deeper level of cleaning, Blessing adds.

Meanwhile, a Qantas spokesperson tells CNN Travel that the airline adopts "the highest standard in cleaning and disinfecting our cabins, seats, galleys and washrooms."

The spokesperson also highlights the HEPA filters which are part of the air conditioning system. "These filters are used in hospital operating theaters, with air in the cabin replaced every three to five minutes. This provides much cleaner air than other public spaces like trains, restaurants, shopping centers and offices."

This echoes the official advice from the Centers for Disease Control and Prevention that, due to the way air circulates and is filtered on airplanes, "most viruses and other germs do not spread easily," but that travelers are still advised to "avoid contact with sick passengers and wash their hands often with soap and water for at least 20 seconds or use hand sanitizer that contains 60%-95% alcohol."

Hong Kong airline Cathay Pacific tells CNN Travel that aircraft cabin cleaning is always carried out to "high standards" -- but some extra precautions are currently in place.

"Out of an abundance of caution, aircraft will be taken out of service to perform extensive additional deep cleaning and supplementary disinfection when a confirmed case of coronavirus has been identified," says a Cathay Pacific spokesperson.

"This includes the replacement of all seat covers, disinfection of all surfaces and galley equipment, detailed cleaning of the lavatories, disinfection of carpets, sterilization of the water system and replacement of air filters in addition to standard cleaning procedures."

Cathay Pacific has also temporarily suspended hot towels, pillows, blankets, magazines and in-flight duty-free on flights to and from destinations in mainland China.

Still, Schaffner says panicked passengers shouldn't feel they need to avoid using in-flight blankets or pillows if they are provided on their flight. There's "no good data" to support the idea they're responsible for transmission, he says.

"It's a consideration that comes logically to the mind, but it's difficult to convince people that they're really low risk. I always come back to the intermediate vehicle [which is] your hands. Do a lot of good hand-sanitizing."

Alves agrees, pointing out that viruses will be eliminated when blankets and pillows are washed. However, he does clarify that there are "knowledge gaps" about the COVID-19 virus and research is ongoing, so recommendations may change.

Staying vigilant

So if you're boarding a flight soon, stocking up on hand sanitizer is the best move. Is there anything else to be done?

Schaffner notes that, from the passengers' point of view, the ultimate way to avoid infections on aircraft is to stay home.

"And there will come a time perhaps -- and some of that is happening already -- where we are being urged to social distance ourselves," he says. "People are reconsidering whether they wish to fly at the moment."

Richard Dawood stresses the important of airlines following the CDC's guidance, but he stresses that travelers should still make up their own mind on whether they should fly:

"Perhaps the most important point to keep in mind is that not a single case of COVID-19 has yet been attributed to on-board transmission," he says.