Another way to get more bang for your buck.

How often does a reservationist ask you, “Would you like flight 100 on the B757 or flight 200 on the B777?” Right: Never. So remember, always ask which aircraft is being used for which flight. Here are a few reasons why.

When an airline has multiple aircraft seat-types Flying New York/Newark-Paris with Continental? The airline services the route with both B757s and B767s. The fares are the same but the seats aren’t. Book a Continental flight for travel on Sept. 1 New York/Newark-London and you’ll have three aircraft to choose from: B757 (CO114), B767 (CO28) or B777 (CO18). Again, the fares are the same for each of the flights, but I guarantee that you’ll be more comfortable on the 777.

While the difference in seats might appear to be minimal, when it comes to comfort, if you’re locked inside an airplane for half a day it’s certainly a game of inches. (Ever heard anyone say how comfortable they were on a 757?) Look at the chart below. It shows the disparity in Continental’s seats on the same routes.

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When an airline is in the middle of rolling out new seats It can take years to accomplish. Take a look at Air France: Fly New York-Paris and you can choose between its B777-W), B777-200, and A340. But only the B777-W) guarantees to have the carrier’s new 180-degree reclining Business Class seats. Other aircraft with the airline’s old seats are worlds apart.

But, of course, the fare is the same.

When code-sharing can squeeze you Book flight AF7 New York–Paris and you’ll fly Air France’s new Business Class, with a 180-degree reclining bed. Book AF8991 and you’ll be flying on a Delta operated aircraft, Air France’s code-share partner—with seats that recline to only 160 degrees and are about three inches narrower.

For the same money.

Book Los Angeles-Beijing on UA4456 and you might be surprised when you get to the gate and find it’s actually an Air China operated flight—not my first choice.

Premium seats vary so widely from one airline to the next these days that you really have to be careful.You’ll find this scenario everywhere nowadays, and it isn’t always easy to detect. Make sure you ask which carrier is actually “operating the flight” so that you know what you’re getting into.

When considering an upgrade to First Class, make sure they have one…

The same goes here as far as being careful, except that in this case it’s not the seat, it’s the entire cabin. Three-class aircraft are not quite Ivory-billed Woodpeckers, but they’re headed that way. So it pays to know which airlines offer it and on which routes. Call it the twilight of the Empire, but BA doesn’t offer First Class on some of its U.S.-London departures anymore. Singapore Airlines has pulled First Class from a number of its routes. American and United also have gone to two classes of service on many routes while keeping a third on others.

So now you know why we often note such details as when an airline rolls out new seats. This stuff is critical: it’s all about your bottom line, especially on a long flight.