SINGAPORE:- The trip between Singapore and the Malaysian capital Kuala Lumpur is the world’s busiest international air route, with more than 30,500 flights between the cities in the year to February, a new study showed. There were on average 84 flights daily making the short hop which takes about an hour, according to the study by air travel intelligence firm OAG. A large number of airlines serve the route, from full-service carriers such as Singapore Airlines and Malaysia Airlines to budget ones like AirAsia. A high-speed railway line is being built to link the cities and is expected to be completed in 2026, cutting travel time overland to 90 minutes from around five hours.