Some people commented saying it was a Chinese lantern in fast wind.
How does a Chinese lantern out-run a helicopter?
How fast does the wind blow?
How fast can a helicopter fly?
How does the flame stay alight in a fast wind?
I think the helicopter would be able to catch up whatever wind speed it was, especially if the same wind was behind the helicopter too!
This video was also shown on Japanese TV
You can hear the pilots conversations and it's without the silly comments and without the silly X-Files music that seems to be dubbed on to almost every UFO story on TV news. (I do not understand everything the Japanese presenter is saying.)