North Korean leader Kim Jong-un is reportedly paranoid about his safety during the summit in Singapore, going to extraordinary lengths to keep himself safe while travelling.
It is only his third known trip outside his country.
When he appeared in China in March he travelled by train, apparently a "special train" used by his father for international travel.
Many observers suggested his mode of travel was in part the result of cash shortages and sanctions that have made it difficult to keep North Korea’s national fleet airworthy.
Kim’s own official aircraft is thought to be a 38-year-old Soviet-made Ilyushin Il-62.
Trump-Kim summit in pictures: Best photos from Donald Trump and Kim Jong-un's meeting in Singapore
It is no longer manufactured and spare parts are becoming increasing difficult to source.
On Sunday, he made the 3,000-mile journey to Singapore aboard an plane loaned to him by China, an American-made Boeing 747 that was formerly used by Chinese leaders — to Kim to make the 3,000-mile trip to Singapore.
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On Monday, the usually closely-guarded leader broke away from summit preparations for a night-time stroll on the Singapore waterfront, even posing for selfies with the city-state’s foreign minister.
In his own country, his appearances are normally carefully managed, with any foreigners present having to go through hours-long security checks beforehand.
Kim had remained inside his hotel all day but a lengthy motorcade emerged from the St Regis in the evening, a North Korean flag flying from his stretch limousine.
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He is due to meet Donald Trump at 9am local time on Tuesday (2am BST).