Many studies have shown that even though e-cigarettes don’t burn tobacco (which creates visible carcinogenic smoke), they do vaporize dangerous chemicals, releasing them into the air. These chemicals, such as formaldehyde, heavy metals, and ultrafine particles, can harm the lungs and cardiovascular system, explains Stanton A. Glantz, Ph.D., professor of medicine and director of the Center for Tobacco Control Research and Education at University of California San Francisco
Note that if you do vape and plan to travel with your supplies, you’re still allowed to carry e-cigarettes in your personal bags in the airplane cabin. You are not, however, allowed to check them in your luggage. A regulation was put into place in October 2015 prohibiting e-cigarettes from being stored in checked baggage due to incidents in which they sparked fires in suitcases.