What do insiders know that you may not? 

When it comes to air travel, little things that can make flights more comfortable or cheaper (or both) and usually cost nothing. Some of this insider advice will surprise you.

For overweight fliers

We've all heard stories about portly passengers getting kicked off flights because they "encroached" on a seatmate's space. That's embarrassing but the airline solution is even worse: big passengers are told to purchase two seats. Who can afford that?  Southwest has a better idea:  Large passengers still have to book two seats but after the flight that second seat will be refunded - even if the flight oversells. I'd call that a win for all.

For thirsty fliers 

We've all walked through security with a bottle of water in hand (which is promptly trashed). Next time, bring an empty bottle and fill up beyond the checkpoint at a designated water refill station. These stations are cropping up at airports around the U.S. and differ from regular fountains in that they're designed to handle large bottles without spilling. Find them in airport terminals in Atlanta, Boston, Chicago (O'Hare and Midway), Denver, Minneapolis, San Francisco, Seattle and more.

For the always-running-late fliers

Maybe you can zip into airport parking and get bags checked fast but what can you do about the lines at security? Plenty, if you join PreCheck; its $85 price tag lets you keep your shoes on as you fly through the checkpoint. Global Entry is even better; for just a couple of bucks more per year, it eases your way through international travel and includes PreCheck. You can learn more here.

For the ultimate frugal fliers 

You put savings over comfort every time which is why you only fly the cheapest airline which we all know is Spirit. STOP! Spirit is not always the cheapest airline because no carrier always has the best fares. True frugal fliers compare ticket prices to be certain of getting the best deal. Sometimes the cheapest fares are on Spirit. Sometimes the cheapest fares are on JetBlue or Virgin America or United or Delta. You just never know. 

For everything-but-the-kitchen-sink fliers

Pack as much as you want but you will pay for it. Some airlines charge up to $200 (one-way) for overweight luggage and that's in addition to the regular $50 baggage fee. On certain international flights, overweight fees can soar to $450. It's simply not worth it to overpack.

For beach fliers

Pack only what you need (good advice for all travelers, actually). Wear something nice on the plane with 'real' shoes and that'll be your go-to nice outfit; pack sandals, bathing suits and a T-shirt or two go in a carry-on for everything else. Bonus savings: If the bag fits under the seat, you'll save some real money on Allegiant, Frontier or Spirit, the only airlines that charge for checked-bags and full-size carry-ons.

For family fliers

If you travel with little ones, bring a bag of distractions and bribes (include cookies as this is no time to play nutritionist). Also bring goodies for seatmates if the kids begin acting up such as a box of candy to pass around, ear plugs or maybe best of all, coupons for free drinks.

For overburdened fliers

Look for a strapping lad (or lass) to help you hoist your carry-on into the overhead bin because some airlines forbid flight attendants to do this (it can result in injuries). If you're worried about hurting yourself with all this lifting, please review number six.

For rude fliers

Never play the Do-You-Know-Who-I-Am card on a plane because the cabin crew doesn't care. Sure, true big shots may get away with it if they are incredibly important (and incredibly rude) but as a veteran flight attendant recently told me, most of these entitled folks are all on private jets these days. Bottom line: there's no excuse for rudeness in small, cramped spaces like airplanes and flights seem shorter when we're all getting along.

Rick Seaney is an airline travel expert and the co-founder of FareCompare.com, an airfare comparison shopping site