Where does the gate drop-off bagage go?
It's typically stored in the cargo bin with the checked luggage.  If it is to be returned to the jetway, it will be tagged with a distinctive tag so that it's clear that it has been screened already (i.e. it came in through security, so it can go back out into the terminal with you at your destination).  In many cases, though, once an item has been gate-checked, it will be delivered to baggage claim to be picked up there.

The exception to that is baby strollers -- they should be returned to the jetway since parents tend to need those to get the young ones around the airport.

Individual airline policies, of course, will vary.  With small jets (not a 737, but a regional jet or turboprop, perhaps), the carry-on space is so limited that all sorts of things that would be accepted as a carry-on for a larger aircraft can't go into the cabin, so those may go into a dedicated cargo hold &amp; all returned as the passengers deplane.