South Korea's budget carriers are coming under fire for a string of mishaps that have raised concerns about the safety of the airlines and the quality of flight crews, local industry sources said Saturday.Sources said the discoveries of a Eastar Jet Co. pilot trying to fly a plane while still being under the influence of alcohol last month and the failure of a Jeju Air Co. pilot to activate the cabin pressurization system after takeoff from Seoul's Gimpo International Airport has caused alarm bells to go off.