How to get a better seat in coach

All coach sets are not created equal. True, nearly every U.S. airline economy cabin is packed like a sardine can these days, but some are packed tighter than others. You can get closer to comfort by being picky about the models of aircraft you fly and then trying to engineer yourself into the best seat on the particular plane you've selected.

I've been comparing a lot of coach cabins lately, tape measure and seating charts in hand. On a Continental Airlines 737 from Newark to Denver, my seat cushion measured 18.5 inches across. The pitch—the distance from row to row, which is a measurement of legroom—was 31 inches. There was no inflight entertainment, and it took some squeezing to get my garment bag into the overhead compartment. For my flight from Denver back to Newark, I opted for a United Airlines 777 instead. My seat cushion measured 20 inches across, the pitch 32 inches. I had my own personal seatback video screen with a choice of movies and television shows, and there was tons of space in the overhead compartment.

Next came an American Airlines 757 from JFK to Seattle. This time my seat cushion measured 18 inches, the pitch 35 inches. My theory that American must be trying to attract the tall and thin was confirmed on my return flight. I managed to snag an exit-row seat: Although it was only 17 inches wide (thanks to immovable, hip-confining armrests), it afforded an extra 7 inches of legroom.

On only four flights, then, I had experienced seats with cushions anywhere from 17 to 20 inches wide and row-to-row spacing of anywhere from 31 to 42 inches, and I had decided it was high time I investigated how coach travelers with a flexible schedule can land themselves the best possible seats. Here's what I found:

Go for two-aisle plans
Wide bodies, which are typically, which are typically used on long-haul and transcontinental flights, have long been more popular than one-aisle planes. They have roomier seats, more storage space, and a less confining—as long as you don't end up in middle seat in the center section. (For a list of wide-bodies used on domestic routes, and their percentage of middle seats, see "How likely are you to get stuck in a middle seat?")

Try for a 767
"It's the only plane ever built with passengers in mind," says Stan Plog, founder of the travel consulting firm Plog Research, Inc. "The other planes were built by engineers who were trying to determine how to have the lowest operating costs." Thanks to its 2-3-2 seating arrangement, and the fact that airlines fill middle seats last, a 767 can be 86 percent full before anyone gets a middle seat. To maximize your opportunity for an empty seat next to you, request an aisle seat in the center section. Another good option is a 777 with a 3-3-3 configuration: It must be 67 percent full before any two strangers are seated next to each other. A 777 with 2-5-2 configuration, on the other hand, need be only 44 percent full before strangers end up sitting in adjacent seats.