Miami International Airport serves as the primary international airport of the Greater Miami Area. One of the busiest international airports in the world, Miami International Airport caters to over 35 million passengers a year. The airport is a major hub and the single largest international gateway for American Airlines. Miami International is the busiest airport in Florida, and is the United States' second-largest international port of entry for foreign air passengers behind New York's John F. Kennedy International Airport, and is the seventh-largest such gateway in the world. The airport's extensive international route network includes non-stop flights to over seventy international cities in North and South America, Europe, Asia, and the Middle East.

Answer this question, if possible (if impossible, reply "unanswerable"): What airline uses Miami International as its smallest international gateway?
unanswerable