The Department of Transportation has proposed a federal rule that would explicitly ban electronic cigarettes on all domestic and international commercial flights in the U.S.

According to USA Today, the department points to a lack of research into the devices' ingredients that could irritate passengers' eyes and throats as justification for the proposed ban.
Smoking in airplanes has been prohibited since 2000 but the current ban does not explicitly refer to the use of electronic cigarettes.
Under the federal rule-making process, the public has until 14 November to submit comments on the proposed ban. Federal officials said they could not estimate how long it would take to review the comments and prepare a final rule for adoption. (pi)