Southwest is expanding NY and Wash.

More slots acquired from Alaska. Adding flights in congested airports is great news...

U.S.The Tennessean
Southwest Airlines adds routes, flights in New York and Washington
Even though the above link doesn't work anymore, the added growth we did in NY and Wash. was a great move by SWA. Now with the recent announcement of Amazons 2 new locations for their HQ-2, maybe we will even grow further or at least focus some of our larger aircraft in these areas to carry more passengers.
Another maybe could be SWA looking at the Max 10 for easier growth within the crowded markets like NY and Wash. where adding flights are more restrictive.
On top of all that good news for growth we also have the 3rd location of Amazon's growth over in Nashville Tn. where they will add at least 5,000 very good paying jobs. With Southwest having almost 55% of the traffic already will be another great growth opportunity at Nashville International Airport. Also another Airport fully capable of handling the Max 10 for more passengers. I really think SWA will be looking at the larger aircraft outside of the 737 soon in the near future. It really will be the only way we can grow at the more congestive airports with restrictive additions of flights...

Business American City Business Journals
Southwest to benefit from Amazon's HQ2 announcement