PARIS (AP) _ European travel officials missed the Americans this summer.

The ''stayaways,'' Americans who didn't travel to Europe during the tourist season that begins in late spring, are expected to cost France $800 million by the end of the year.

Dutch officials estimate they have lost about $110 million.

''This is serious because Americans tend to spend more than others,'' said Bret Annerer, vice director of the Interlaken tourist office in Switzerland.

European hotels catering to Americans have been severely hit. The Intercontinental in Paris, for example, reported 60 percent of reservations made by Americans were canceled.

Overnight stays in Sweden fell by 35 percent in May and June, said Birgitta Olausson of the Swedish Tourist Board.

In Austria, the number of U.S. hotel guests dropped by 60 percent in June, according to the Austrian Hoteliers Association said. Denmark recorded a 26.7 percent decline in American guests in May.

On the whole, European travel officials said the number of U.S. visitors along with the revenues they bring dropped by 30 to 60 percent. The falloff in visitors started after U.S. warplanes bombed Libya and the Chernobyl nuclear accident in the Soviet Union in April.

Not all Americans, of course, were put off.

In London, Olive Leonard Pruski, a tourist from New Orleans, said she was too busy sightseeing to worry about terrorism or fallout from the Chernobyl accident.

''Our only concern is finding our way around London,'' said Mrs. Pruski, who was visiting Trafalgar Square with her daughter and granddaughter.

The Europeans reacted quickly to the decline in American tourism and began aggressive advertising campaigns, offering discounts on hotels and airfares in an attempt to coax the Americans back.

In Venice, Italy, where U.S. tourism was down 60 percent, a campaign called ''Supper at the Palace'' was launched. Two dozen Americans each week enjoyed a romantic, elegant evening out, with the bill paid by the tourist bureau and hotel owners' association.

France capitalized on its ties to the U.S. Statue of Liberty celebration. Air France offered free charter tickets to couples buying tickets by July 4, the Galleries Lafayette department store gave a 10 percent discount to U.S. customers on that day, and the tourism minister made rounds at the big Paris hotels, greeting American guests.

The tourism problem in France had been compounded by U.S. resentment of the French government's refusal to let American jets fly over on their way to targets in Libya.

Now tourism officials in several countries are cautiously saying the worst is over. Although official figures are not in, hotel bookings and airline reservations have rebounded.

''The signs of a recovery are unmistakable,'' said Aafke Huininga of the Netherlands Bureau for Tourism.

''We already see a silver streak on the horizon, as bookings by individual tourists begin to rise slowly again for the coming months,'' agreed Karl Heinz Mueller, a marketing analyst for the Austrian Tourist Promotion Board.

But no one has predicted a return to the banner year registered across Europe in the summer of 1985, when the dollar was worth about 40 percent more in international exchange.

''Europe now becomes very expensive and this keeps them away,'' said Stael Von Holstein of the Association of European Airlines in Brussels.

''Many have already been to Europe when it was cheap and this is why they don't come a second time when they think there might be nuclear dust around,'' Holstein said.

Heinz Illi, director of the tourist office at Lucerne, Switzerland, said the main problem was the decline of the dollar, not fear of terrorism or radiation.

''Americans react very spontaneously and also forget events easily,'' he said. ''Europe is still an attractive destination.''