It was still near the peak of the summer travel season, but an eerie silence reigned last week in Concourse D at Denver's Stapleton International Airport. Nearby, the entire 42-aircraft passenger fleet of Frontier Airlines sat grounded. In the terminal building, there were occasional scenes of chaos as anxious Frontier passengers, left stranded by a sudden shutdown, scrambled to find other airlines that would accept their tickets. As the paralysis wore on, groups of Frontier's 4,700 employees huddled in airport corridors and union halls to glean the slightest rumor of their fate.
Money-losing People Express, Frontier's troubled, no-frills parent, had pulled...