These seats are the best ones in coach

Choosing the right seat when you're flying coach can determine whether your flight leaves you cramped and cranky -- or rested and relaxed.

Not all coach seats are created equal, points out CBS News Travel Editor Peter Greenberg.

And on "The Early Show" Friday, he revealed the secrets to picking the most comfortable seats in coach - and not breaking the bank doing it.

The coach cabin has become a hodgepodge of different comfort levels and amenities. When legroom is so precious, which seats offer a few more inches? And which ones should you avoid?

According to Greenberg:

When you think about a coach seat, most people want an exit seat or a bulkhead seat (where you sit and there's a wall in front of you.) They both sound like a good idea, but most exit seats don't recline, and their armrests don't move. With bulkhead seats, you have no place to put your stuff. The only reason you'd want a bulkhead seat is if you're a family traveling with small kids.

But, the best seats vary when it comes to airlines and airplanes, depending on the type of plane you're flying on. Whether it's a Boeing 757, 767 or 747, they're all built totally differently. So, when you're making a reservation, find out what kind of plane you're flying on and then check out a web site like SeatGuru.com, where you'll find the configuration of any commercial flight that can help you pick the best seats.

There's no premium on any of these seats, but you have to know to ask for them when you're making your reservation on the phone or online. The further in advance you know, the better your chances are of getting them.

Typical 757

You can find 757's with Delta, United and American (among others). With a 757, ask for seats 10A and 10F. They're the best because there's an exit door in front of the 10th row in the 9th row which means that there's no 9A or 9F, so what you're getting is a window seat with unbelievable leg room. You actually have enough room to stand and move. And if, for some reason, you get locked out of these seats, try getting the exit row.

767s

On American, you want 17H and 17J. The reason is that on overseas flights, they're used as crew rest seats, but on domestic flights, they're not so that's why you want them. They recline better than other coach seats and have more leg room.

FULL SCREEN: AMERICAN 767 (LOGO & plane laid horizontal)

REVEAL: seats 17H and 17J in GREEN (labeled)

747

A middle seat often sounds like the worst seat on a plane and sounds like you're going to prison, but on a coach flight, they're often the best. Looking at the configuration, you'll see that (depending upon the side of the plane you're on) middle seats have no seats to the right/left or diagonally in front of you, so you have lots of space. If you look around, it's the area where the tail tapers in and the plane becomes narrower in the back. It's the middle seat (with the same lettering as the rest of the middle seats) that most people dread but is best because there's no window seat. There's side space and leg space.

Sometimes, planes have different configurations, so it pays to pay attention, Greenberg says. The wall Street Journal notes that there's sometimes a huge disparity among the same seats at different airlines. Spirit Airlines' new Airbus A320s have a knee-busting 28 inches of space for each coach row, while JetBlue Airways has a standard 34 inches in its A320s and several rows with 38 inches of space (seat and legroom combined) for an extra charge. On the same airplane, Spirit squeezes in 178 seats, while JetBlue carries only 150.

How can you avoid getting the worst seats on a plane?

Always book your seats when you reserve your flight, and keep in mind that airlines often hold back 30 per cent of all seats to be assigned and designate them for airport check-in only -- meaning those assignments are under their airport staff control. Get to the airport that much earlier!