The FAA in the United States uses prototypes for high-activity control towers, which explains why there's so much duplicity.
The first prototype was introduced in the late 1960s - a slender concrete tower designed by I.M. Pei. You can find them at JAX
and several other airports.
The second prototype - the four pillar design - was introduced at Dallas/Fort Worth in 1974. You can find them at COS
, and a few others. It's been largely phased out, although some middle-level airports, such as MSY
, have built them in the last decade.
The newest prototype premiered in 1992 at DTW
. They've since been built at DFW
. Some airports have taken this design and added some architectural flourishes to it - LAX
, for instance.
There's also a lower-tier prototype for less-busy jet airports, which you can find at SAN