Here's the deal: Yes, your metabolism affects your size, and the faster your personal motor runs, the more calories you'll burn. But the truth is, a slow metabolism isn't the real reason you're packing on pounds. You are the reason.
As a general rule, arrive at the airport no later than two hours before your domestic flight is scheduled to depart. This is somewhat later than the typical suggestion of three hours for an international flight.
The UMNR must be brought to the airport by a parent/guardian. Delta recommends arriving at the airport at least 90 minutes prior to departure time for domestic flights and 2 hours prior to departure time for international flights. Please keep in mind, some airports have specific cut off times for check-in.