Originally Posted by
poisson
Here's an example of a real hastle.
A French friend was flying from Paris to Tahiti. He had a layover in Los Angeles. Because the US makes EVERYONE go through customs and passport control, regardless if they just have a layover, he had to obtain his bag, go through customs and passport control, then recheck the bag.
Technically, he was not entering the US and his final destination was non-US.
If I flew NY - Frankfurt - somewhere in Africa, I wouldn't be required to touch my checked bag, or show my passport in Frankfurt.
The large majority of people arriving in the US from overseas are ending their trip somewhere in the US. This isn't true for the major European airports. In general, even for the major international hubs in the US, a large portion of passenger departures are domestic.
As an example, look at FRA. 88% of the passengers leaving FRA are headed outside of Germany. (
http://www.fraport.com/content/frapo...stics-2013.pdf, see slide 23)
For JFK, international pax represent only 56% (
https://www.panynj.gov/airports/pdf-traffic/ATR2013.pdf).
Bottom line, US airports aren't set up for intl-to-intl connections for quite good reason, and reconfiguring them to handle them would be a massive undertaking, particularly since terminals are often carrier-specific, rather than be domestic or international specific. Combine this with the fact that the US doesn't have structured exit controls, and hence no checkpoints to keep people bound for international flights from going back out of the terminal, it's a massive challenge.