southwest.com now associates the two, so if one types in CLE, Cleveland area airports show both. It wasn't like this when CAK became a WN station months ago. I wondered why such a simple thing wasn't done, but now the website groups the two like SFO, OAK, SJC.

It seems southwest.com removed FLL and PBI associativity, with only FLL associated with Miami.

So, there might be no DTW and FNT grouping happening. FNT is over 60 highway miles from Detroit, as PBI is over 60 highway miles to Miami. Although the FNT-Florida and other flights possibly maybe supported by those Ann Arbor and Detroit metro area, or those reaching these regions.