Get the luggage lowdown. Find out how many bags you're allowed to carry on and to check, and if there are any weight restrictions. Most major airlines now charge between $20 and $50 for a second checked bag -- and some make passengers pay for the first. Keep gifts you're carrying unwrapped, even if they're packed in your luggage, to make the security check easier. If you've got a lot to carry with you, you might want to consider shipping gifts and gear a week or so before you leave. Ground delivery might be less expensive than extra baggage fees. Visit the Transportation Security Administration at tsa.gov to find out about limits on carry-on gels and liquids, including baby food, formula, and breast milk.