SINGAPORE - North Korean leader Kim Jong Un's trip to Singapore for talks with U.S. President Donald Trump poses logistical challenges that are likely to include using Soviet-era aircraft to carry him and his limousine, as well as dozens of security and other support staff.The choice of Singapore as the site of the first-ever meeting of a sitting U.S. president and a North Korean leader was as much because it was within reasonable flight time and distance from Pyongyang as because of the island state’s political neutrality, a South Korean presidential official told reporters.Since becoming North Korea’s leader in 2011, Kim has only taken one known overseas trip by air – and that was earlier this week to Dalian in China to hold talks with Chinese President Xi Jinping. He flew in his personal Ilyushin-62M jet accompanied by a cargo plane that people with knowledge of North Korean affairs say is believed to have carried his limousine."It looks very much like the trip to Dalian was a dry run," said Andray Abrahamian, a research fellow at Pacific Forum CSIS and formerly with Choson Exchange, a Singapore-based group that trains North Koreans in business skills.At 4,700 km from Pyongyang's Sunan airport, Singapore is easily in the range of the Il-62M aircraft. The Soviet-era narrow-body jet with four engines was first introduced in the 1970s and has a maximum range of 10,000 km.But the Ilyushin-76 cargo plane cannot fly more than 3,000 km without refueling if carrying a full load. It will therefore have to stop off at a friendly location like Vietnam’s capital on the way to Singapore or fly with a reduced load.The Il-76, originally designed for moving heavy machinery to remote parts of the Soviet Union, is big enough to fit a school bus or two shipping containers inside it, according to passenger and cargo flight operator Antarctic Logistics & Expeditions.But the cargo plane has had some safety issues. In the latest incident last month, a crash killed 257 people on board after takeoff from an Algiers air base. Unlike his father Kim Jong Il, who died in 2011 and who traveled by armored train on his rare trips abroad because he feared being shot down, according to a North Korean defector familiar with his security details, the younger leader is not known to be averse to flying.But air travel of this distance does pose a significantly greater challenge in transporting communication and security equipment and personnel needed to back up a summit meeting.