[FabHK]

None (it's not like Lesotho inside South Africa or San Marino inside Italy). I assume he meant destinations where most international flights go via the US, but not sure that's relevant - I'm pretty sure basically all South American countries have direct flights to Europe or Canada, say.

[matt4077]

It can be prohibitively expensive to find a flight from Europe to the Caribbean or Central America that doesn't involve a stopover in the US.