Add-on airline fees for extra services that used to be included in fares are increasing in price and changing frequently, making fare comparison shopping more difficult, according to a new TravelNerd study.

Roughly 69 percent of the 52 fee changes at major U.S. carriers during the past year were direct fee increases, according to the survey. TravelNerd, a developer of online and mobile app travel tools, compared add-on fees at 14 major American airlines in January 2013 to those charged by carriers in 2012, tracking each fee change. Add-on fees are for services such as checked baggage, priority boarding and preferred seating.

And hold onto your pocketbooks and mental energy.

Airlines are creating complex new ways to charge for ancillary services — in some cases bundling or packaging those amenities together and offering fliers combined services at a discount to what they would cost on a one-off basis. (Read more: Add-On Airlines Fees: Good or Bad?)

Iberia Airlines today unveiled new cabin improvements to its long-haul fleet of Airbus wide-body jets, including fully lie-flat seats in business class.

The new business and economy class seating sections in Iberia's fleet will debut on eight new Airbus A330s the airline receives in February. Iberia's existing fleet of A340 aircraft will be converted throughout the year with the cabin upgrades.

The introduction of fully lie-flat seats follows a growing trend in the airline industry to provide first-class comfort in business-class cabins. (Read more: Delta Joins Other Airlines to Offer Lie-Flat Seats)

Atlanta's Hartsfield airport has the best services and amenities of any in the United States and scored top marks for business travel and connecting flights, according to a poll released on Tuesday.

The southern hub was also voted the best airport for dining, and placed third for activities to keep children occupied, the survey by Travel Leaders Group found. (Read more: Atlanta Airport's Sleek New International Terminal Opens)

Nearly two weeks after the Federal Aviation Administration grounded the 787 Dreamliner, Boeing Chairman and CEO Jim McNerney is confident they will get the beleaguered line of planes back in the air. "Our first order of business is getting the 787 back into service," said McNerney. "We're all concerned and want to get to the bottom of this quickly."

Social media has become an important tool for airlines to communicate with travelers, and some carriers use Twitter more effectively than others, according to a new study.

Skift.com, a resource for industry news and market data, studied the behavior and popularity of U.S. airlines on the instant-messaging platform. Some airlines are chattier than others, and a couple barely have a social presence at all. Where does your favorite carrier rank? And beware: a large following doesn't guarantee an engaged community.

I traveled to Tokyo last week and was greatly anticipating a five-star experience onboard United Airlines in international first class. But my optimism proved greater than the service I received.

Certain elements were indeed solid, such as comfortable seating and an ample selection of food and beverage choices. Other aspects, however, fell significantly short of similar overseas trips in first class I've taken on premier airlines, including Asiana, Cathay Pacific and Lufthansa. My last international trip on United was much more of a success. (Read more: Road Warrior Tested: United Airlines International Business Class)

Read on to find out why this flight disappointed in my Road Warrior Tested series.

At a time of heightened security concerns, disgruntled airline employees and frustrated passengers can be a combustible combination in a crowded aircraft, as travelers find themselves subject to lots of rules and little wiggle room to challenge them.

On a United Airlines flight from Zurich to Washington Dulles International Airport on Jan. 2, Bill Pollock asked a flight attendant about a sign telling passengers not to venture beyond the curtain separating economy class from the rest of the plane. Mr. Pollock, a book publisher from Burlingame, Calif., said he wanted to stretch his legs and visit his wife seated on the opposite aisle, using the passageway behind the galleys in the plane's midsection.

(Read more: Best Seats: United Airlines Boeing 757-200)

If you missed hitting Gold or Platinum elite frequent-flier status with American Airlines for 2013, you may get a second chance—for a fee.

American this week will reach out to certain frequent fliers who missed the threshold in 2012 to requalify for Gold or Platinum status in 2013, offering an opportunity to buy the coveted status back.

(Read More: American Luring Frustrated United Fliers With Status Match)

Delta Air Lines will break the traditional boundaries of airport lounges with the introduction of new outdoor terraces at its Sky Clubs in Atlanta and New York.

Delta has partnered with Architectural Digest to develop the airline's first-ever outdoor sections of its lounges dubbed "The Sky Deck."

Michael Leon is adamant about his fear about the use of lithium-ion batteries on the Boeing 787 Dreamliner.

"These lithium-ion batteries are heat intolerant. Too much heat on those things, they will go into a thermal runaway, they will explode, it will be a nightmare," he said.