How Will Kim Jong-un Travel to Vietnam for Summit?
I would not be surprised if he used the Chinese plane again just for safety purposes; a train journey from North Korea to Vietnam just seems too long of a trip to take though it would be a pretty awesome way to see China:
North Korean leader Kim Jong-un flew to Singapore on a rented Air China plane, instead of his aged official jet, last June for his first summit with U.S. President Donald Trump. What he will use to travel to Vietnam’s Hanoi for a second meeting with Trump is a point of speculation that will likely remain a mystery until his arrival there.
Yonhap
Many say Kim is likely to fly on the state jet, codenamed “Chammae-1,” this time because the distance of travel, about 2,760 km, is only slightly more than half of the 4,700 km flown last June, and the Soviet-era jet, even if it’s aged, can sufficiently cover the flight.
But others say that Kim could rent a plane from China again if he places priority on safety.
Some even suggest that he could use his special train to travel all the way to the Southeast Asian nation through China for the Feb. 27-28 summit, just as he traveled to the neighboring nation by train last month, noting that Vietnam also has the same rail specifications as North Korea.
You can read more at the link.
Since Xi is going to be at the Summit as well as Moon, I am sure there will be plenty of chances to him to hitch a ride either by borrowing a plane from China like he did with the Singapore summit or maybe his buddy Moon will give him a lift.