Originally Posted by stut
Also, I was quite surprised at which part of the BP you retain in the US and Canada. Standard, over here, is that they retain the larger part of the BP (with the ticket insert - if ATB, it can be inserted, stapled or printed over, depending on the airline) and you retain the stub only. This has a slit or a hole for hangers. As it's credit card sized, it's quite convenient to keep hold of...
Aha...the last time I flew, I noticed the slit in the middle for the first time ever (okay, I can be slow sometimes) and wondered what it was for! Another mystery solved...