If most airport checkpoints are useless security theater, the worst airport in the US is a high school version of Our Town, and Frankfurt airport is every Cirque du Soleil playing simultaneously at the Bellagio with Celine freakin' Dion singing on your lap.
Stay far far away.
We made it eventually, but I'm about to collapse as I type this. Also, the Mercedes B-Class will have to wait; Sixt discontinued them a few weeks ago [not that they bothered to remove them from their reservations site, of course]. We got a 5-door BMW 1-Series instead, and so far it rocks. Pleasant surprise. [btw, did you know I've been writing a travel journal/column about these back-to-back overseas trips at Babble.com? There's a bit of a publishing pipeline-related timelag, but there's also an abundance of chatty details and advice for toddler travelers. Check it out.
We passed through Frankfurt due to a changed flight on our way back from Barcelona a month ago. They were randomly ejecting EVERYONE from the secured area at various intervals making you throw out any food or beverages you had purchased in the secured areas before you could go through another even more invasive security screening to get back to the boarding area. For some reason the duty-free flammable alcohol purchased in the boarding area was safe to come back through but the water and snacks were not.