An expert weighs in on how to prevent dryness, dullness, and puffiness after flying.A woman in a spa getting a facialCredit: Vesnaandjic/Getty ImagesThere’s a dizzying amount of planning and preening before jetting off on a getaway, but the one area that often gets neglected prior to air travel is skin preparation. Ever heard of "flight face"? You know the dreaded look: dry, dull, and puffy—the post-flight aftermath of a long trip or a red-eye r…