For those trying to quit smoking, e-cigarettes are being lauded as a less harmful alternative to inhaling thousands of chemicals.

However, deciphering the legal haze around smoking e-cigarettes on airplanes is not easy.

"Under the Non-Smoker's Health Act, and its pursuant regulations, smoking is prohibited on board commercial and charter aircraft for health reasons," said Transport Canada spokesperson Karine Martel.

"Transport Canada is not aware of any safety risk to the aircraft machinery that would be caused by the vapour from e-cigarettes."

The Non-Smoker's Health Act defines smoking as to smoke, hold or otherwise have control over an ignited tobacco product. However, e-cigarettes are neither ignited nor tobacco products.

Instead, they function by electronically vapourizing a liquid, which usually — but not always — contains nicotine. That mist, which is sometimes flavoured to taste like mint or candy, is then inhaled.

Health Canada has not approved e-cigarettes for sale in Canada but has also not legislated any ban against them. 

In the same vein, Transport Canada currently does not have any specific rules banning the smoking of e-cigarettes on airplanes.

For the time being, it would appear the government is leaving the decision up to individual airlines.

"Air Canada does not permit the use of e-cigarettes onboard aircraft," said airline spokesperson Angela Mah.

However, the airline's policy regarding carry-on baggage does allow e-cigarettes onboard "provided they remain stowed and unused."

WestJet spokesperson Brie Ogle says while the airline typically refers questions regarding e-cigarette safety to Transport Canada, it does have a policy saying the devices cannot be operated while onboard.

Ogle says the airline has not yet had any complaints about anyone smoking e-cigarettes on flights and are not aware of anyone having tried to do so.

'No smoke to set off any alarms'

For years, smokers on airplanes have been warned during the flight safety demonstration that smoke detectors in plane bathrooms are installed to detect any cigarette smoke — but neither WestJet, Air Canada or Transport Canada would confirm whether they can detect vapour from e-cigarettes.

However, Australian e-cigarette manufacturer Egar states on their website that the product "only emits harmless water vapour, which will not set off smoke alarms." 

The company claims their product can even be used on planes.

Darren Clark tweeted to CBC Calgary saying he has smoked onboard aircraft without setting off the alarms.

"I've done it," he said. "As long as [you're] discrete nobody bothers and there's always the washroom — no smoke to set off any alarms."

It seems airlines themselves are not entirely sure whether smoke detectors can pick up on e-cigarette vapour.

Porter Airlines spokesperson Brad Cicero says he is not aware of whether the airline knows about e-cigarettes not setting off smoke detectors.

Ogle also says she did not know for sure whether the devices would set off detectors.

It's also not clear whether those caught 'vapeing' — the term e-cigarette users use to describe the process of inhaling the vapour — would face similar fines to those caught smoking traditional tobacco products while onboard.

Canada leads in aircraft anti-smoking rules

In 1994, Canada became the first country to require that its air carriers make all flights — domestic and international — smoke free.

At that time, the momentum for change came not from passengers but from airline employees.

"Sitting on a long flight having to endure cigarette smoke, while dangerous for passengers, is far more dangerous for flight attendants who have to work in a blue haze," Donna Hendrick, an airline employee's union representative, said to CBC News in 1994.

Much of that push was based on discoveries linking cigarette smoke to increased risk of cancer and health effects.

The Calgary Eyeopener's medical columnist, Dr. Raj Bhawdwaj, says there's no clear consensus on whether e-cigarettes are safe but their perception as a safer alternative to traditional smoking could undo much of what anti-smoking advocates have fought for.

"A lot of people are saying they are allowed to 'vape' because they're not smoking, and the anti-tobacco lobby is up in arms about this," Bhawdwaj said.

"I think part of the solution would be to regulate them not as a drug delivery device but regulate them as a tobacco product — which is sort of outside the realm because they're not tobacco," he said. "But that's a huge job."

What do you think about people being able to smoke e-cigarettes on aircraft? Leave your thoughts in the comment section below or tweet us @CBCCalgary.