It claims that one of the top international routes is MCO-SJU. That's a domestic connection. That's Orlando to Peurto Rico. That's a US territory and you don't need a passport to go.
Orlando is in the US, and San Juan is in the US. That makes it a domestic flight.
Also, Paris/French Polynesisan https://en.wikipedia.org/wiki/World%27s_longest_domestic_fli...