8. Macau SAR, China* to Shenzhen, China. 30 miles. (Tie)
* Since 1999, Macau has been part of the People's Republic of China as a Special Administrative Region or SAR. However, with differing visa and customs regulations, flights between Macau and mainland China are treated as international flights.
6. Saba, The Netherlands to Sint Maarten*: 24 miles.
*Sint Maarten is a constituent country of The Kingdom of the Netherlands.