Originally Posted by
Mwenenzi
off topic
Many countries require you to clear immigration & customs, with all your bags, at your port of entry. Some countries allow customs, if any, at the final domestic destination.
A USA oddity is no airside international transit (without immigration customs, etc). USA require full entry (visa, immigration etc) even if only in USA for a few hours to board another international flight. Not aware of any other country that requires that (but may be some).
Probably why most people don't / won't transit here. Why would a Brit fly into EWR to get to YYZ when there are numerous alternatives. It would have to be a screaming deal for me to do it given my experience with US customs. As I recall years back, probably pre 911, MIA had a transit area where those traveling into the Caribbean and South America could transit through but apart from that I don't ever recall a US transit airside zone.