This has been answered countless of times: people say "this airport might be interesting" but, when it comes the time to spend the hard earned money, it always the most obvious destinations that prevail, which means that people buys where they fly the most, which is usually on their own area, at least their continent, because not many people have the time to fly for many hours, the average it's usually 1.5-2 hours flights.
Which means, we'll concentrate on US and Europe for the foreseeable future. This is also related to availaibility of documentation. Not just charts and aerial shots, but 3d representation of buildings from all sides, which are not usually available outside US and Europe. This is not a small part of the decision what to do: it's basically the most important one, we just can't model anything without precise information.
For example, an airport like KFLL, although not being a mega-hub, it's a very convenient destination, because it's located in an area were hundreds of important places are within easy reach. The same for Zurich, O'Hare, JFK and KLAS.
However, we are working on something else right now, which is not an airport scenery and it's not an airplane, and this is our main task right now.
The next airport that will start as soon as KFLL (but probably after the Summer, because sometimes even our people gets vacations...), will be another mid-sized airport like KFLL. There are several likely candidates, and all of them have been requested many times here so, I'm sure that, whatever we'll decide to do, it will please many people. It's more likely to be in the US, though.
About KDFW, is still scheduled to be done, but we need to complete the "other" project first, which has been started for a while, and has to be released. KDFW hasn't started yet, BTW. We know how important it is, that's why we need to be absolutely sure we can afford to do it right, and giving it the time it deserves.
This doesn't have anything to do with the release of KFLL and the next one because, as we said already, we have two set of people working in parallel and the LZSH-KORD-KFJK-KLAS team is busy right now and I don't think it will be available before September to begin KDFW, while the LSGG-KFLL team will be doing the next airport.