Last month I posed a simple question: Are airlines withholding seats so you’ll pay a premium? We asked for your thoughts. And, boy, did we get them: In nine years of writing this column, I have never received as many e-mails and online comments.

And according to you the readers, the answer is an unequivocal yes—something fishy indeed is definitely happening behind those airline screens.

A common problem 

Let’s clarify: Some readers declared this a longstanding practice, citing the yield management methodologies airlines have employed for decades. But this is not about purchasing an airline ticket, which every traveler knows is subject to some of the most arcane and byzantine pricing practices on the free market. This is about selecting an economy-class seat with your purchase, and finding that most “free” seats are occupied, forcing you to consider paying extra for “premium” seats.

Last month I detailed my difficulty selecting two economy-class seats from an online seat chart filled with premium seats, only to find the flight was just 30% occupied on the day of departure. And in dozens and dozens of cases, passengers, travel agents, and even corporate travel managers detailed how they too were unable to secure seat assignments—on AirTran, Alaska, American, Continental, Delta, JetBlue, United and US Airways. (Only Frontier Airlines received kudos.) This phenomenon also was reported with foreign carriers, and when booking through third-party travel agency sites.

Your stories detailed traveling companions sitting apart, including parents separated from small children and handicapped passengers separated from their partners. You told how you paid extra but felt duped in cabins filled with empty seats.

From among the more than 100 responses we received, here are some key observations:

•”A week before our trip my husband noticed that most of our seat choices had been ‘dropped’ and we had to re-select seats. We were able to secure adjoining seats on all flight legs except one. [The seats] were not together and were considered ‘premium’ and therefore would require more money…We felt forced to pay!!”

•”It’s downright fraud.”

•”Most disturbing is the recent trend of downsizing planes and/or cancelling [flights] without notification after booking.”

•Even elite frequent-flier members have complaints: “In the past where I would get my upgrades consistently five days ahead, that was no longer happening despite the plane not being full. Airlines have no real obligation or penalty if my miles or upgrades cannot be used…At some level I am concerned that airlines are getting away with their practices because they can.”

•Others advocate strategies that could be risky: “One suggestion is NOT to get a seat assignment…Then 24 hours prior the site will still prompt you to buy extra-cost seats, but if you decline and still check in—voila! It will assign you the very same ‘premium’ seats.”

•”I’ve learned the tricks of the trade—if I can’t get seats together, then I buy all aisle seats, which are better for bargaining…It’s usually not too hard to find someone to trade middle to aisle.”

•And only one reader was happy: “I’m sure this is not a popular opinion but I like the seating policy. As a Delta frequent flier I find the attention to the most loyal passengers refreshing.”

Airlines: ‘Perception is inaccurate’ 

Last month a Delta spokesman stated there are “so many variables” it’s difficult to detect such a trend. In fact, I contacted several major carriers, and the official responses indicate this is all coincidence. “It’s not something that we do,” said a spokesman forUnited Airlines. “Aside from a certain number of seats, the overwhelming majority of seats in economy are available for selection.”

Eduardo Marcos, American Airlines‘ director of merchandising strategy, explains: “To ensure that non-elite customers that value seat location have an opportunity to pre-reserve seats near the front of Main Cabin, we set aside a small percentage of Main Cabin seats, and make them available for purchase. These seats, called Preferred Seats, are available for purchase from the time of initial booking, up until the airport check-in cutoff time, beginning at $4 per flight. Elite customers as well as active military members traveling on military fares have complimentary access. Most seats in Main Cabin continue to be available for pre-selection at no charge.” So why are so many customers reporting a dearth of regular economy seats and an abundance of Preferred Seats? “This perception is inaccurate. As stated, most seats in Main Cabin continue to be available for pre-selection at no charge.”

One reader responded to the question I posed by stating all responses are “pure speculation.” Well, that’s the point. Consumers do not have the tools to confirm such practices, so that’s why many advocates are suggesting the U.S. Department of Transportation investigate.

Calling DOT 

Many are convinced that so many customers can’t be wrong. In fact, some readers question the legality of such practices: “I made the selection to purchase the tickets. However, when the tickets were issued, a note stated the seats would need to be assigned at check-in or at a kiosk … Why did the airline misrepresent the information to me when I was purchasing the tickets? That is illegal.”

“It’s a shell game with the seats,” says Al Anolik, a veteran travel attorney and expert on aviation law. “When they tell me seats are not available and they are available, they are lying.” Anolik claims the key is full disclosure, and passengers should be given their options: “I can appreciate yield management, but there is a line that is drawn by misrepresenting [available] seats. In this case, silence is the same as deceit.”

• MORE: What are your rights when you fly?

Along with other traveler advocates, Anolik believes the DOT needs to intervene on behalf of airline passengers on this issue. But he notes that DOT intervention is often driven by consumer complaints, and suggests readers should speak out. You can learn more about filing complaints online, by mail or by telephone at the DOT’s Aviation Consumer Protection and Enforcement site.

In the meantime, every airline problem eventually induces entrepreneurs to create solutions. ExpertFlyer offers the Seat Alert product, which allows you to sign up for an e-mail advisory if a seat you prefer opens up. A free account allows you to create one alert at a time, or you can pay on an ad hoc or monthly basis for multiple alerts.

• MORE: Read previous columns

Bill McGee, a contributing editor to Consumer Reports and the former editor of Consumer Reports Travel Letter, is an FAA-licensed aircraft dispatcher who worked in airline operations and management for several years. Tell him what you think of his latest column by sending him an e-mail at travel@usatoday.com. Include your name, hometown and daytime phone number, and he may use your feedback in a future column.