US-PARIS AIR TRAVEL GROWS CHEAPER, EASIER

For Americans musing over a vacation in la douce France - or for Frenchmen tempted by a trip to the Wild West - this could be the best summer yet to follow the dream.

Capacity on airlines traversing the Atlantic between destinations in the United States and France will be up more than 30 percent this year.

The increased traffic, led by US carriers, is causing friction and this week led the French government to cancel a post-war agreement loosely regulating US-France air traffic. The French hope to work out a new accord that will better protect their industry. But in the meantime, the boost in transatlantic capacity will be in effect. And that will mean generally lower fares and some bargain deals, travel specialists say.

"There's been a marked and steady fall in prices of flights over the North Atlantic just in the past couple of years," says Jean-Pierre Faure, a travel agent here. "It's got to the point where the US is an affordable destination for the average Frenchman." Round-trip flights between Paris and the US East Coast now start at less than $600. "You can even find some at 2,000 francs," less than $400, Mr. Faure says.

The greater affordability of flights is largely the result of deregulation in the US airline industry. Until 1984, air traffic between the two countries was shared by TWA and Pan Am on the US side, and Air France. Now eight US airlines fly to Paris, increasing both capacity and the number of US destinations served.

The growth in service has caused mounting fears at Air France that the profitability of its North Atlantic routes would suffer. Earlier this year, when the US carriers proposed a 45 percent (500,000-passenger) boost in the number of seats to France, the French finally accepted a 30 percent increase. But they served notice that they want to negotiate a new deal.