(Cleveland) -- Travelers are losing six almost new nonstop flights from Cleveland Hopkins International Airport. Frontier Airlines announced yesterday the cancellation of service from Cleveland to San Diego, San Francisco, Los Angeles, Charlotte and Houston. A Frontier spokesman would not confirm whether low ticket sales doomed those routes, but airline industry analysts tell Cleveland.com there is a lot of competition from traditional and low-fare carriers on those routes. Frontier still serves 13 destinations out of Hopkins.