I'm a warm shower host in Incheon, Korea
Incheon International Airport in Korea is located on an island, and you have to take the airport railroad to get out from there.
Bicycles are only allowed on weekends to use airport railroad.
On weekdays, it doesn't matter if bicycle is packaged by cardboard box and sum of 3 sides is under than 2mtr.
Other all subways is only allow 158cm. But airport railway is different.
Many guest worried about 158cm and I hope other traverller is no more worry about that.
Korea is super hot. Hopefully visit after 2 or 3 weeks later.