Delta Air Lines earnings have given the sector's stocks permission to take off early Thursday. The carrier's numbers beat expectations. It offered improved full-year guidance that came in ahead of Wall Street estimates. Significantly, the airline said sales trends have accelerated across all geographies in the past six weeks. That was enough to send the shares, and those of its peers, higher in early trading. Delta jumped 6.5% ahead of the open, while United Airlines was up 4.6%, and American Airlines climb ...