• If you use your cellphone, the plane will crash.
• Cruise ships are all-inclusive.
• If you rent a car with a credit card, you don't need additional insurance.
• Taking the train in Europe is cheaper than flying.
• Recirculated cabin air on planes will make you sick.
• X-ray machines at airport security checkpoints can erase your computer's hard drive.
• Your hotel card key can be used to steal your identity.

These are just some of the things many travelers believe to be true. And, in fact, with a couple of qualifications, they are nothing more than the latest batch of travel myths.

Let's start with the Blackberry/cell phone myth. Every airline flight attendant makes more or less the same announcement, insisting you turn off your cellphones and Blackberries, blueberries, strawberries and other personal electronic devices because "they interfere with the plane's navigational systems." If you ask if it's a rule, the flight attendant will tell you it's FAA policy. True or false?

False on both counts. First, the FAA has tested personal electronic devices, including iPods, Gameboys and laptops. Their scientists -- for more than 25 years now -- have bumped up the RF interference these devices give off, up to 100 times their normal levels, at distances of less than three feet from sensitive cockpit avionics. And guess what? Nothing happened. Nothing has ever happened. So did the FAA make a rule? Or a policy? Not exactly.

See slideshow: Seven Common Travel Myths

• Also see: 12 Ways to Avoid Airport Delays
• Also see: How To Avoid Airport Lines

Under the current federal air regulations, the FAA simply states that it was unable to prove any connection or link between operating these devices and airplane system interference. But it hasn't made a rule; it's left to each individual airline to set policy. So, if you insist on ignoring the flight attendant by using your Blackberry, you may be in violation of an airline's policy (and subject to arrest for interfering with a flight crew). But no, the plane won't crash because you were sending emails.

First-time passengers like to think that "all-inclusive" cruise means you can put your wallet away for a week. True or False?

Keep your wallet with you. Not long ago, what you paid for your cruise (exclusive of liquor) was the sum total of expenditures. Not anymore. Think of cruise ships today as multiple floating revenue centers. Some cruise lines are now charging a flat fee for unlimited soda, and even a wine-and-dine deal that includes wine or champagne with your dinner (about $125 for a seven-day cruise). But the key to cruise ship profitability can be summed up in two words: onboard revenue. A new rule of thumb for budgeting your next cruise: Take the basic cruise fare and multiply it by 1.75 per person.

See slideshow: Seven Common Travel Myths

• Also see: Annoying Airline Charges
• Also see: 10 Travel Secrets of Frequent Fliers

Oops, you just backed into a parking meter. Not to worry, your personal auto insurance covers damages to your rental. True or False?

The answer in most cases is true, but with a big warning from us. Credit card companies promote their promise to cover your insurance if you rent a car using their card. As a result, a number of unsuspecting renters who don't own a car -- and thus don't have their own insurance -- think they are covered by their card. Not so. Almost all credit card companies offer something called "secondary insurance," which only kicks in when you've exhausted all the limits of your primary policy. And if you don't have a primary policy, then you are not covered at all. Even if you are covered, check your policy limits. If the car you own (for which you pay personal insurance) is only worth $5,000 and you total a car worth $20,000, you're out $15,000.

Trains are the way to go within Europe if you want to save money. True or False?

Definitely false. While I have always been in love with trains, and I think back fondly to my days using a student Eurail Pass, the dollars-and-sense truth today is that trains are not economical alternatives to air travel. Low-cost European airlines are now cheaper than intra-European train travel. On Ryanair, an off-season round-trip flight from Rome to Frankfurt can be as low as $90. By comparison, a point-to-point train ticket from Rome to Frankfurt starts at $326 each way and takes about 12 hours of travel time.

Many travelers contend that the way cabin air is circulated makes the plane a prime breeding ground for colds and flu viruses. True or False?

In my experience, the answer is a qualified true, but there is no scientific proof. First, the cabin air: Modern jet planes were designed to bring in air from the outside at high altitude. In theory, the extremely cold air (about 40 to 60 degrees below zero) is then heated by the aircraft engines and circulated into the cabin, purging the old air. But there's a problem. This procedure costs fuel and fuel costs money, so many airlines simply recirculate the air already onboard the cabin, bringing in a very small amount of new air. So you may well argue correctly that if the person in seat 2B has the flu, you'll be breathing his air back in 35E. But to date, no definitive scientific studies have proven that allegation. Still, my advice is to hydrate yourself while on the plane, wash your hands often and turn off the air vent over your head.

See slideshow: Seven Common Travel Myths

Also see: How to Beat Jet Lag

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