Alaska Airlines in May again was the most punctual major U.S. airline

with an on-time performance ratio of 89.6 percent, according to FlightStats. Among the eight largest carriers, Delta again ranked second, at 86 percent, while American Airlines ranked last at 77.1 percent. Among all North American airlines, Alaska Air Group subsidiary Horizon had the best on-time performance during May (91.7 percent), followed by Hawaiian (90.9 percent). At 67.8 percent, Spirit ranked at the bottom. Vancouver again landed at the top of North America airport rankings, with an on-time performance ratio of 91.4 percent, again followed by Salt Lake City (89.9 percent), according to FlightStats data. Newark had the worst on-time ratio among North American airports at 68.2 percent.