– Most people have a few things they won’t board a plane ­without. For Randy Petersen, it’s a tape measure.

Petersen belongs to a small army of independent airline reviewers who fly around the world intent on gleaning information he says many carriers have “abdicated from providing” — such as the amount of legroom in coach.

The inside track on cabin layouts has become a hot commodity in an industry where fist fights have broken out over the “right to recline” and the number of spare seats has dropped nearly 10 percent in a decade, reducing the odds of being able to stretch out into an empty berth. That’s especially so in economy class as discount carriers win a bigger slice of short- haul flights, and mainline and charter operators offer wildly differing personal space on trips that can span 16 hours.

People pore over measurements — and the locations of toilets, galleys and exit rows — because seating is one of the few aspects of travel under their control, said Andrew Wong, Asia-Pacific director at TripAdvisor Flights in ­Singapore.

“The flight could be late, the meal terrible and the staff rude, but at least you can choose your seat,” he said.

While some carriers, like Singapore Airlines’ low-cost arm Scoot Pte, make clear on their websites the dimensions of all seats, others are less forthcoming.

Delta Air Lines offers seat width and pitch information, but online the charts it provides to compare premium seats to basic don’t include the specifics. Instead, consumers must click into a section ­offering airport and aircraft information.

Cathay Pacific Airways, one of only eight airlines worldwide with a five-star rating from airline-review service Skytrax, doesn’t post seat data on its website, though an official e-mailed the numbers to Bloomberg News upon request.

Other carriers are quick to stress the plush look of plane cabins but give less ­publicity to the dimensions. When British Airways revealed plans for a refit of 95 Airbus Group NV A320 jets in June, it emphasized the use of charcoal-gray leather and mood lighting, without quantifying the impact on legroom or the introduction of an extra row of seats in economy class.

This coyness stems partly from the fact that “it’s not quite apples and apples” as new seat designs emerge, said Peter Harbison, executive chairman at the CAPA Centre for Aviation in Sydney. Pitch, the standard metric used by comparison sites, measures the distance between the seat surface touching a passenger’s back and the same point in the row in front, and doesn’t correspond directly to legroom.

In the case of the British Airways refit, the pitch remained at 30 inches in coach, even though extra space was secured by using thinner cushions and moving the magazine pouch to head height. At the same time, the pitch in ­business class was cut by 4 inches in order to accommodate the extra row, a move that reflected a shift of emphasis to “the whole package” rather just legroom, BA spokesman Euan Fordyce said.

“It’s definitely important information when there’s a choice of international ­airline,” said Darren Wakefield, who runs aussieflyer.net in Melbourne, from where it’s a 24-hour journey to Europe and almost as long to New York. “One extra inch of space can make a big difference on a long-haul flight.”

While most information published by seat-comparison sites comes from manufacturers and airlines, including so-called Layout of Passenger Accommodation diagrams used by engineers and regulators to show the position of all seats, it takes the human touch to fill in the blanks.

TripAdvisor’s seatguru.com website relies predominantly on feedback from its 3 million monthly visitors to reveal less obvious features, such as seats without a ­window.

At Seatexpert, Petersen, who is based in Colorado Springs, thinks nothing of taking a dawn flight from Amsterdam to Helsinki just to check the measurements on a refurbished Finnair Oyj Airbus A319, though he specializes in more amenity tips, such as which seats give the best view of the Grand Canyon.

Airline-review sites can also boost the chances of finding an empty seat next door, something that former Boeing Co. executive Klaus Brauer — who helped guide the planemaker’s product development efforts — said in a blog post is “still the biggest discriminator in passenger satisfaction.”

The possibility of that has receded sharply as airlines combat overcapacity, with 80.4 percent of seats filled industrywide last year, compared with 73.5 percent in 2004, according to the International Air Transport Association.


Star Tribune staff contributed to this report.