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.
Luckily, today there are a variety of ways to minimize the time you need to arrive at the airport in advance to make your scheduled departure. Arriving two hours before a flight isn't always necessary (provided you don't require extra time or aren't a part of a group). There are some excellent strategies you can implement to skim that two hour-protocol down to one.