3:39 p.m. FAA Orders Nationwide Ground Stop on All Departing Flights

USA: The Federal Aviation Administration on Friday ordered a ground stop on all departing flights at U.S. airports.
The agency’s advisory said the stop was issued “due to extraordinary circumstances and for reasons of safety.” It gave no further explanation, saying only that “all departing traffic should remain ground stopped until further notice.”
No other details have been released, including what prompted the order or how long it will last. This is a developing story, and updates will be provided as more information becomes available.