I grew up in the FL Panhandle, and like someone above correctly referred to it as "podunk," it is most definitely DL territory.

My closest airport at home is ECP. We have DL, WN, and UA express. I've found DL and WN pricing to be within $30 or so on routes they both serve. I always prefer DL to earn Skymiles (as devalued as they are), but most importantly for the ability to confirm a seat assignment in advance. This, to me, is very valuable when traveling with a companion. UA only has 2 flights a day on RJs, not at good times, and usually is significantly more expensive.

Go east towards TLH and we have DL, AA (eagle), and 3M (Silver). AA has good frequency, but the fares are always out of sight. Silver is a total wreck and unreliable. Better to take the DL flight north to the ATL and then go back south to central/south FL.

DHN to the north is exclusively DL connection.

Further west lie VPS and PNS. Too far of a drive in my case to consider.

Now that I live in ANC I'm still on DL to get home to see family, and the vacation routes (both domestic and international) I am researching for the eventual trip look to be best on DL. If I decide to vacation on the west coast somewhere I might consider AS (especially to HNL). But my company has me fly to SEA twice a year on AS and to me the planes always have a strange smell and are stuffy.

The only time I truly was disappointed in DL was the storm meltdown this past April. I was among the thousands stranded in SEA and the entire vibe of the SEA employees were that they just gave up. I ended up booking a one-way on WN to get to ECP and payed for business select (it was only $28 more) and enjoyed early boarding and free drinks.

The only thing I really wish DL would do is to lower (remove is not likely) their change fees. I can totally understand a difference in fare, but the change fee can be rough. Oh, and make Skymiles great again!