Jeju Air is adding seats on China routes as a surge in passenger demand, led by younger travelers and independent tourists, pushes load factors higher across its network. The airline said Monday that it provided about 494,300 seats on Korea-China routes from January through July, up 26.8 percent from about 389,900 seats during the same period last year. Passenger numbers rose even faster, reaching about 427,300, a 37.4 percent increase from roughly 311,000 a year earlier, while the average load factor climbed to 86.4 percent from 79.8 percent. The airline said the sharper rise in passengers than capacity reflected growing travel demand following visa-free policies between the two countries and an increasing preference for short-haul trips. Travelers in their 20s and 30s accounted for about 158,500 passengers, or 37.1 percent of the total, making them the largest age group on the routes. Among the routes popular with younger travelers were Busan-Shanghai, Jeju-Beijing Daxing and Incheon-Qingdao, which recorded load factors of 89 percent, 89.7 percent and 93.5 percent, respectively, from Ja