Carol - Back in the day, and by this I mean in the early 70's, we couldn't imagine there would be as many daily nonstop flights to SXM as there are today and yet, look what happened. At first, we could only fly to SXM via San Juan, then we got nonstop flights from JFK and it was only over the course of years that MIA, CLT, BOS, and others were added. It isn't just about adding new cities though. Airlines operating out of New York and Chicago could choose to fly to/from LaGuardia and Midway because landing fees are lower for them there then they are at JFK or O'Hare. The same is true in many cities. It will just depend on what is most efficient for the airlines and passengers will adapt as they always have. Again though, the bigger prize for the airlines is being able to avoid scheduling their arriving flights to coordinate with US Customs and Border Patrol here in the US.

As for as the stats, in 2016, the last full year of stats pre-Irma, there were 528k "stay over" visitors who arrived in SXM by air. Some of those continue on to other nearby islands so perhaps we can assume the right number for SXM is about 500k. A five fold increase would mean 2.5 million arriving by air or 2 million more than there are currently. As some have rightly noted, this would overwhelm the current infrastructure of the island. A five fold increase may be a wild over estimate though. But, even a three fold increase, from 500k to 1.5 million, would mean an extra 1 million stay over visitors a year. These kinds of numbers get the attention of the island's government because it means there will be increased investments made in the island, more hiring of local workers, more taxes paid by both businesses and tourists and so forth. All of which is good for the economy of the island.

In terms of the order of things, I agree there is no question that the airport has to be restored to at least its prior operating capacity before adding additional traffic. However, since the powers that be are, hopefully, planning a design with an eye to the future, it makes sense to include pre-clearance facilities in the design. The timing of when pre-clearance goes live, can be decided once regular traffic is back to normal.