Major U.S. airlines are drafting plans for a potential voluntary shutdown of virtually all passenger flights across the U.S., according to industry and federal officials, as government agencies also consider ordering such a move and the nation’s air-traffic control system continues to be ravaged by the coronavirus contagion.No final decisions have been made by the carriers or the White House, these officials said. As airlines struggle to keep aircraft flying with minimal passengers, various options are under consideration, these people said.But amid the quickly spreading pandemic and...…Major U.S. airlines are drafting plans for a potential voluntary shutdown of virtually all passenger flights across the U.S., according to industry and federal officials, as government agencies also consider ordering such a move and the nation’s air-traffic control system continues to be ravaged by the coronavirus contagion.No final decisions have been made by the carriers or the White House, these officials said. As airlines struggle to keep aircraft flying with minimal passengers, various options are under consideration, these people said.But amid the quickly spreading pandemic and...WW…