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Is Economy plus really worth the price?

Delta Air Lines's Economy Comfort seats have up to 4 inches more legroom and recline 50 percent more than the airline's standard international economy class seats.

How much is a good night's sleep worth? $40? How about $350? I flew to London recently in Delta's new Economy Comfort section, where a few inches of legroom made the difference between a cramped, miserable night and a peaceful sleep across the Atlantic.

Economy Comfort is the latest "premium economy" section from a U.S. airline. These are sections at the front of coach where, for a fee, you can get the legroom people used to take for granted. The premium economy market is chaotic, though -- the term means very different things at different airlines, for very different prices.

Let's start with Delta. Delta just laid in 36-inch Economy Comfort seats on most of its international flights, with the same class coming to domestic flights soon. Economy Comfort comes with free booze, AC power ports, and those precious few inches of legroom.

I've flown transatlantic in Delta coach before, and the industry-standard 32-inch legroom is just a little bit too tight for a good night's sleep. Just a touch. And I'm 5 feet 7 inches tall. On my Economy Comfort flight over, I sat next to a guy whose knees were up to his nose even in the 36-inch seat.

On my way back, the AC power outlet was the key amenity -- I could watch my own movies without worrying about running out of battery on an eight-hour flight.

Buying the seat was a no-brainer at $40 each way, because I'm a Delta gold frequent flier. For non-status fliers, that would have been $80. I'd still do that one way, though, to keep that good night's sleep.

What Is Premium Economy, anyway?

"Premium Economy" typically means a seat towards the front of the economy class section with more room and early boarding privileges. It isn't nearly as cozy as business class, and you don't get business class food or service. But if it doesn't cost a lot more, it can take some of the edge off of flying.

Along with Delta, United, Virgin America, Frontier, JetBlue and Spirit all offer premium economy seats. Prices vary but they can be reasonable, especially if you need those extra inches of legroom because you're 6-feet tall or want to sleep on a red-eye.

Read more: Compare prices and offerings of most U.S. carriers

Is it worth it?

For a while now, we've been struggling with two competing desires in travel: the desire to pay incredibly low prices and the desire to be treated like human beings. So far, the airlines have found that Americans' and Europeans' cheapness tends to win out -- thus the success of Ryanair, and the shrinking of airplane seats pretty much everywhere on both continents.

Premium economy seems like a good solution, provided it's reasonably priced, and for domestic flights, it usually is. For a little more money, you get a slightly better product. Business class fares are out of the reach of most Americans; $39 for some extra leg room isn't.

Unfortunately, only Delta is right now doing a reasonably-priced premium economy seat for international flights. United almost qualifies, but it's still more expensive, and you don't get any more room than Delta. On some planes, you get less: 35 inches to Delta's 36.

Yes, just-plain-"economy" should be like today's Economy Plus. But for tall travelers, long-haul travelers, or even just slightly cramped travelers, it's definitely worth looking out for, and worth paying a little more for.

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