Alaska Air Group (NYSE: ALK) has been rapidly pulling in passengers as it competes against much-larger rival Delta Air Lines (NYSE: DAL), with Alaska Airlines passengers up 9.7 percent in the first half of the year. The growth in flights has been accompanied by slightly more empty seats, with 84.6 percent of seats filled, off 1.6 percent. On-time arrivals also were off, by 1.1 percent. To be sure, Seattle-based Alaska seems to be staying ahead of Delta in on-time performance.