There are two that I have seen that are particularly interesting.
One is the STL
masterplan. This includes the oft maligned third parallel which is staggered so far to the west from the current runways that its ability to enhance capacity is diminished. Additionally, it is too close to the other parallel runways with spacing of less than 4300 feet.
Phase Two includes concepts for renovations to the existing terminal along with new additions. The renovation appears to involve removing the gates that sit along the main taxiway now, thus, restricting two-way taxiing. This is crucial to providing access for departing and arriving flights to and from the new runway. However, this appears to be many years away if it ever happens.
There is a provision for a west terminal and associated roadways that sits a bit close to the runway protection zone (RPZ); that building has what appears to be widebody gates - presumably for Asia and Europe flights that are currently non-existent.
West of the crosswind is a 50-60 gate airside. This would give Lambert a total of 130-140 gates. All of this is based on demand by the airlines - and God knows they're all chomping at the bit waiting to add more flights here. I mean O&D appears to be up - especially for airlines other than American, but this is hardly the hub it once was.
If anything, the old facility should be bulldozed - including the current East Terminal (Southwest and charters). All carriers should be housed in a new terminal. the proposed design of the midfield concourse has different sections to allow separate areas for various carriers.
Check it out at http://www.tisp.org/files/isbe2004/panel_2b/griggs.pdf
St. Louis' other airport MidAmerica-St. Louis has two carriers and is slated for expansion of cargo service. The powers-that-be are so afraid of losing Lambert to Illinois that they have effectively squelched the possibility of this much larger land mass being the major St. Louis area carrier facility. The "Fleecing of America" TV
specials didn't do much to help. check out this site:
The other airport with terminal expansion is Detroit. Now that they have completed their midfield and are finishing its expansion, they are moving forward with North Terminal - a variation on the linear terminal/concourse theme which includes a sort of "W" shaped concourse. This will replace the Smith and Berry terminals.