[aside headline="The Seating Plan" alignment="alignright" width="half" headline_size="default"]STEP 1: Use the Internet to view aircraft types and seat configurations. Orbitz.com and other online booking engines allow you to look at a specific flight’s seat map by clicking on “View Seats.” You’ll be able to see exactly how many seats there are in Business and First Class. STEP 2: Use the “View Seats” link to see how full a flight is. Go with the flight that has the most seats available, but keep in mind that the seat map doesn’t reflect those passengers who have booked and haven’t requested seat assignments yet. But if a seat map is filled, the flight is full, so look elsewhere if all you can do is wait-list. STEP 3: Ask the reservationist to check the number of premium seats still left for sale. Specifically, ask the person to check the “availability screen,” which shows how many “deeply discounted” seats are still unsold. (These are usually A, D, I, and Z class.) If there are many of these deeply discounted seats left on a given flight, your chances of getting an upgrade are much higher.[/aside]

We all know how the law of supply and demand works, and most premium travelers also know that when it comes to upgrades, the law often works against them. The reason is simple: The supply of premium seats available for upgrades on any given route, whether domestic or international, simply doesn’t meet the demand for them. One way to improve your odds is to plan your itinerary around the aircraft type. Business and First Class cabins on the various models differ greatly in size, so choosing the one with the most premium seats can be a key move, especially as most airlines do not overbook First or Business Class. As business travelers often change their plans, the plane with more seats has more seats likely to open up—clearing the way for those waitlisted. Here’s a look at how cabins compare on some in-demand routes.

Domestic Differences On its Los Angeles-New York/Newark route, Continental operates B737-800s (16-20 First Class seats), B757-200s (16), and B757-300s (24). If you’re a OnePass elite member, book the B757-300 flights and you’re much more likely to get an upgrade confirmed.

Hawaii: United operates B757s (24 First Class seats) B767s (34), and B777s (36). American serves Hawaii from the West Coast using mostly B757s (22 First Class seats). But the savvy traveler will notice some flights from Los Angeles to Honolulu operate with B767s, which have 30 First Class seats. The B767 seats also offer much more legroom and recline further than those on the B757.

The Best International Flights to Upgrade Here’s the golden rule: B747s trump B777s. And Boeing usually trumps Airbus. That’s right: On almost every route I’ve looked at, the B747 carries more Business Class seats than the B777, and offers more premium seats than Airbus’ long-haul models, although this can vary by airline.

Take British Airways, for example. It uses both Boeing aircraft on its New York-London route. The B777 has 48 Business Class seats, while the B747 has 70 seats. Lufthansa’s B747s on the New York-Frankfurt route have 50% to 100% more premium seats than its various Airbus configurations.

The same rule can apply across the Pacific. On the San Francisco-Tokyo route, some United configurations have as many as 73 Business Class seats while others have only 45.

Make better connections: Have your reservationist determine which city offers the most advantageous connection, based on seat availability as indicated by seat maps.