There are pleasant surprises and hidden pitfalls. Here’s what to look for.

It’s been several years since Amex put out a press release announcing new (or dropped) members of its International Airline Program (IAP), which offers free companion tickets on 18 airlines. The program’s web site is even outdated, only showing partnerships valid for travel though Dec. 2006. Malaysia Airlines is no longer a partner, a big loss for those seeking bona fide First Class seats to Asia, but you’d never know it from the web site. Delta has joined, but offers companion fares from only three departure cities: Atlanta, New York, and Salt Lake City. What’s worse, many destinations Delta is offering are second-tier cities, for instance Bucharest and Kiev. Delta’s 2-for-1 fares are only applicable with the highest fares and often don’t even beat the cost of two of its own discounted Business Class fares. As for Continental, it offers some good fares on long-haul routes, but only from Cleveland, Houston, and New York/Newark—though you’d never know this from the Amex web site either, as it only charts the destination cities permitted.

What’s changed the most since we last reviewed the program In many cases, the Amex 2-for-1 is more expensive than two regular discounted fares, which have been on the decline to many destinations (when booked 14 to 50 days in advance). So, here’s a crib sheet that tells you when to consider a 2-for-1.

North America

Mexico: Go to your travel agent or look online first; fares have dropped considerably in the past few years as First Class seat supply exceeds demand. AeroMexico: Often only a $100 savings through IAP program—better to go with your preferred carrier. Delta: Usually no savings. The lowest Atlanta-Cancun published First Class fare is $978 round-trip, while it wants $2,322 for two tickets through IAP. Other routes can be even worse.

Caribbean: Overall, they’re the same as Mexico for First Class fares. But Continental’s free companion deals can save you a few hundred dollars (and without the advance purchase that deeply discounted fares require). But remember, the companion doesn’t earn miles on that ticket.

Long-haul

Africa: Generally good in Business Class, always good in First Class. Air France, Austrian Airlines, Emirates, Lufthansa, South African Airways, and SWISS all offer Business Class fares. The only airline to offer companion First Class seats is SWISS.

Asia: Asiana, Cathay Pacific (one of the program’s gems), China Airlines and Emirates offer good values much of the time, with Asiana the best for First Class.

What’s changed? Japan Airlines fares have skyrocketed. China Airlines and Asiana offer the lowest fares.

Europe: For business travelers, Amex free companion fares shine, since this was the program’s original target market. Travelers flying on short notice or who can’t stay over a Saturday night will find that the second ticket is indeed often free. This applies most to members serving Europe: Air France, Air New Zealand, Alitalia, Austrian Airlines, Continental, Delta, Lufthansa, SAS, SWISS, and Virgin Atlantic. Of these, SWISS is the only one offering 2-for-1 tickets in First Class.

South America: Both Continental and LAN offer good values and solid Business Class seats.

South Pacific: From Los Angeles, Air New Zealand offers great fares—another one of the program’s gems for both business and leisure travelers. Emirates and South African Airways are also decent options from the East Coast. Emirates offers First Class service New York-Perth.

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