So true as I found out trying to look for an international destination for my vacation. Only one. CUN was available both ways and only on one day per week (not reassuring during Irops) . Others I could either get there or get back but not both.

Costa Rica for example is only from BWI. Likely becoming the longest of WN flights leaving so early and returning so late very few possible connections exist going to or from.

But I do agree if they would enable a click through on Kayak to Southwest.com they'd get more business probably at lower cost rather than letting any online TA have access to GDS booking capability. They are seemingly already paying for an ad on Kayak.

EDIT: I rechecked several destinations again and many of them are now available. Possibly related to different reservation systems taking a few more days to load as I checked originally on schedule extension.

After some thought... After each route takeover some return bookings may have been hurt by Airtran routes being previously listed and booked on OTAs... Booking on an OTA would have shown outbound on Airtran w/no Airtran return and probably included return on a different airline. That should fix itself.