(FORTUNE Magazine) – Now that U.S. airlines have massively consolidated, how do you like air travel? Well, for better or worse, brace for more as international carriers head down the same runway. Says Sanford Rederer, vice president of strategic planning at Trans World Airlines: ''Like any other mating dance, this one is very pleasant for those who participate and will only lead to frustration for those who do not.'' The mergers are just getting under way. Argentina is said to be shopping part of its national carrier, Aerolineas Argentinas. Iberia and Lufthansa have created a joint charter carrier, VIVA. Air France, British Airways, and KLM have all bought stakes in European regional carriers. Pan Am is threatening to sell off pieces of the airline if its labor unions don't take pay cuts. Other major carriers, U.S. and foreign, are signing agreements to cooperate on marketing, computer reservation systems, and operations such as ticket sales and check-in. United has what it calls a marketing merger with British Airways. BA will sell United's services along with its own in the U.S. and across the Pacific, and United will represent BA in Europe and the Far East. They'll share ticket offices in cities where they overlap and will negotiate for catering and fuel as a duo. United cut a similar deal with Alitalia in June. Such moves may be precursors to outright mergers, especially in Europe, where all sorts of trade restrictions will disappear in 1992. Says Geoffrey Lipman, executive director of the International Foundation of Airline Passengers Associations in Geneva: ''When they're sitting in the boardrooms later on saying, 'If we have to merge, who are the likely candidates?' they are clearly going to look at those they've already entered into subsidiary arrangements with.''