Stacy K. Martin, president of the Transport Workers Union Local 556, which represents more than 10,000 flight attendants, knows these gadgets are coming, but is not sure what he and others will be able to do about them.

“We’re not policemen. We’re not going to be able to get anything done if we have to ask people if they’re wearing sunglasses or computer glasses and if their watch is a computer,” Mr. Martin said. “My hope is that we will get some relief from the F.A.A., but I don’t expect them to step up and be prepared for these issues in a timely fashion. Technology is clearly 10 years ahead of the F.A.A.”

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10 years.