How DHS's threat to cut customs processing in sanctuary cities could snarl air travel everywhere

• Do those airports have room? DFW, Charlotte, and Miami are already busy airports, and American has only so many gates and so much room in its schedule at each airport each day. How does it weave in Flight 101 and the two other flights from London that arrive at JFK each day?
• What about staffing? The airline has gate agents, ramp workers, baggage handlers, and contracts with caterers, cleaners, and other staff at the airport. Will there be enough people to work the additional flights that are diverted to different airports? If not, what does the airline do? Send workers from JFK to Dallas? If so, for how long? And where does it house them? Who pays?
• What about passengers? Of the passengers aboard Flight 101, from London, let’s say one was going on to Santa Ana, California; two were going to Des Moines, Iowa; and five were going to Chicago. What happens if American lands the flight at its Miami hub? It doesn’t have direct flights to Santa Ana from there. So does it have to pay to put those passengers on another airline to get them to their destinations? Or does it have to fly them to somewhere else in its network — say, Dallas-Fort Worth — that can get them to their final destinations? In that case, who pays?

  And those Chicago and Des Moines passengers: Let’s say the American flights are already full that day. Are the passengers just stranded? If not, how do they get to where they want to go? Does American have to figure that out, or are the passengers on their own? And again, who pays?

Take the entire state of Texas, for example. It has a blanket “no-sanctuary-cities-allowed” policy, so airports such as Dallas-Fort Worth, Houston, Austin, and San Antonio could, in theory, take on additional traffic under Mullin’s proposal.

But not every airport can handle every aircraft. San Antonio, for example, has a shorter runway than larger hubs, which can limit larger long-haul widebodies and reduce passenger or cargo capacity, and therefore, revenue.