@ablaze @aaronpk Ah ok, that makes sense. I did some research on it couple of years back, and FAA always deferred to individual airlines to make the call on that. The airline has the authority to disallow calls, but it's not an FAA regulation. Some in-flight companies (like GoGo) explicitly forbids VoIP calls in their ToCs (at least used to) that you agree to when you join their network.
@ablaze @aaronpk Did you by any chance grab the pamphlet/page from her? I'm not aware of an actual VoIP ban by FAA, but flight attendants sometimes confuse it with regular cell calls. Although, many carriers block VoIP calls via their in-flight WiFi, due to noise complaints, etc, as well as bandwidth concerns. Some technologies work around that, but if VoIP is "blocked" (as far as they're concerned) and you're on a call, you're more likely to be mistaken for doing a cell call.