Sunday I will be traveling through JFK for an international departure on DL. A few hours later, a colleague is also going to be at JFK for an international departure. The problem is that I need to pass a carry-on (nothing too exciting - business samples) to that colleague, and he won't arrive until after my departure.

In ancient times, I would have thought that I might successfully ask the personnel at the lounge if I could leave that bag in their care, but in an era of "heightened security" I don't know if they would accept the idea of leaving anything "unattended", even though it obviously already would have been through TSA screening on the way in.

Do any of you have any experience with this question, especially at JFK? Can I even trust that his European departure on DL from JFK will leave from the same terminal as mine?

If that approach seems unviable, any other ideas? Even if there is still a left-luggage facility somewhere (and I know that most airports have long since removed them) it would surely be on the land-side somewhere, and of course I would rather avoid having to go back through security unnecessarily (but recognize that I might have no choice).

Thanks for any advice.