It's important to get the details correct. The aerosol created when the battery vaporizes some of the liquid in the cartridge is not "then released into the air." Due to how the devices are designed, all of the vapor created by the e-cigarette is inhaled by the consumer. The vapor that is exhaled has been filtered through the lungs of the vaper. National Business Group on Health provides misleading information, relying on a since debunked 2009 press release from 2009.
Recently, Dr. Igor Burstyn of Drexel University completed a meta-analysis of studies on toxins in vapor. He pointed out regarding exposure to users, none of the chemicals found in vapor rise to the level of exceeding occupational health hazards and stated, "Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern." Several studies have shown that although there is some nicotine in inhaled vapor, there is no nicotine in exhaled vapor.
The Department of Transportation does not have a rule in force that prohibits using an e-cigarette on airplanes. If they issue a final rule with that prohibition, it will be challenged in court.
Speaking of which if employers aren’t willing to risk their legal and moral obligation to provide a safe and healthy workplace for workers they should seriously consider whether they should endanger the health of employees who are former smokers by prohibiting use of the
device that made their abstinence from smoking possible. Employers can decide to consider the devices in the same realm as nicotine gum, patches, inhalers, and nasal spray that are used long-term to prevent relapse.