While cell phone use on airplanes has generally been discouraged, some flights have in-flight Wi-Fi provided through a cellular connection. With the right support on the carrier and device sides, or the right app, this can be used for Wi-Fi calling. Since an aircraft's cabin tends to be a cramped space and some people are rather uncomfortable with the notion of cell phone use in any capacity on a plane, the US Department of Transportation has put forth a proposal to warn fliers when they're on a voice call capable flight so that they know the feature is at their disposal, and to expect others to be using it on the flight.
The widespread use of calling on flights could cause controversy for obvious reasons, and this proposal seeks to stem some of that controversy. Right now, a bit of research in advance could land you on a plane that's able to accommodate continued communication Rather than that approach, the proposal at hand would have travelers notified upon seeing the flight and being able to pay for the in-flight Wi-Fi as it would be able to provide Wi-Fi calling.
Naturally, such a notification could also serve as a cue for passengers who aren't too keen on having voice calls going on around them to hop another flight. Should somebody find a flight without voice call capabilities or in-flight Wi-Fi, they will be able to go through the entire booking process without any notifications relating to the features, aside from their absence from the listing. Regulations in the US currently only concern the use of a cell phone in the air via a cellular network, leaving Wi-Fi calling unregulated. This proposal, if it passes, would be the first official law on the books regarding in-flight Wi-Fi calling. It should be noted, however, that the Department of Transpiration is actually looking at banning Wi-Fi calling on flights altogether as a possibility. The Department of Transportation first brought up the idea of a proposed rulemaking for voice calls back in 2014, which was met with many saying that they don't want people making calls on planes, and they are seeking public comment on the matter. Comments on the current docket have to be in before February 7.