Corbeck, I recently started a desk job with UA, and my group has been working on a system that has made me quite familiar with the ZED pricing process. While UA agreements aren't necessarily going to be the same as US's, the fact that they are both on Star Alliance means that they will probably be pretty similar. I can't check for all airlines, but if you'd like to you can PM me a stack of routes and airlines and I'll do what I can do to find their prices. Each one only takes a minute or so. If nothing else, it should tell you which airports have shockingly high departure taxes, and which ones are reduced if you're flying through an airport (some taxes are waived if you go through a city as a connection).