Actually SWA not hubbing is not real true any more, if it ever was. They have many major stations where lots of airplanes arrive and depart having swapped passengers. That’s functionally a hub even if they don’t call it that for marketing reasons. Off top of my head their quasi-hubs now are DAL, MDW, STL, ATL, BWI, PHX, & LAS. I may have missed one.
What they do do, much more than the other mainstream carriers, is route aircraft like Hub 1- ABC - DEF - GHI then to Hub 2. So they can carry pax ABC - DEF, ABC - GHI, and DEF - GHI without ever touching a hub. Nowadays with more hubs the most common pattern is Hub1 - ABC - DEF - Hub 2. So the direct outstation to outstation flights are an ever-shrinking percentage of the whole.
This is a different approach to providing regional service, which the other carriers supply with their regional affiliates. It’s also mostly a legacy of the Wright amendment which required them to leave Dallas Love (DAL) (their original HQ/hub)and land in one of the adjacent states before continuing farther away. So they went DAL - OKC - Denver instead of DAL - OKC - DAL & separately DAL - DEN - DAL.
As to full flights and disruptions, the whole industry is that way. If we’re running 90% load factors and one flight cancels, it’ll take 10 flights= ~2 to 10 days to squeeze all the displaced pax onto the remaining seats to their destination.
The truth is that a lot of travel just gets cancelled outright. If you can’t get to Grandma’s on the days you have vacation you don’t go at all. If you don’t make the business meeting on Tuesday, showing up on Thursday won’t work for the people you’re meeting. So the meeting is rescheduled for two weeks hence.
To be sure everybody that’s away from home needs to get back. But if the customers delete or defer 2/3rd of the outbound travel that solves 1/3rd of our overall problem. Hertz / Avis also do quite a business. As an employee trying to travel non-rev I’ve had to drive 1500 miles to get back home from a trip when I got caught out when a disruption hit. I was far from the only person in line at the rental car place that day looking to one-way a car back home.