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.
Usually for an international flight (out of europe) you should be there about 3 hours before the flight. for a European flight, u can be there 2 hours before the flight. But to be honest there is no point turning up that early unless you plan to go shopping at the airport, otherwise you will wait around for ages.