Since Aug. 10, when a ban on most carry-on liquids sent the amount of checked luggage soaring, airlines have been misplacing many more bags, and the fumbling could well escalate during the busy holiday travel season. The Transportation Department reported that 107,731 more fliers had their bags go missing in August than they did a year earlier, a 33 percent increase. It got worse in September, with 183,234 more passengers suffering mishandled bags than a year earlier, up 92 percent. Globally, about 30 million bags are mishandled each year, according to SITA, a company that sells software to airlines and...