AMERICANS TOOK MORE TRIPS this year than last, according to new industry estimates. The increase was 5 percent over 1986, says Travel Industry Indicators, a trade monthly. Air travel on domestic United States and international routes was up 12 percent over '86 (with fares up about 2 percent). Overseas travel by Americans increased 20 percent, while visits to the US by travelers from other countries rose 17 percent. LUXURY OLYMPICS PACKAGES are offered by two Canadian National hotels from Feb. 4 to March 31 in connection with the 1988 Olympic Games at Calgary. The Hotel Vancouver and Jasper Park Lodge are offering a rate of $99 (US) for deluxe accommodations, including breakfast daily, tickets to special events, and use of the swimming pool and exercise equipment. These packages are designed for enjoyment before and after the Olympics, which are some distance from the hotels. For toll-free information and reservations, phone 800-268-9143. A FREE DAY OF SKIING FOR BEGINNERS will be offered by some 200 US ski areas Jan. 8, and reduced-price follow-up packages will be offered through Feb. 7 in a promotional program called ``Let's Go Skiing, America!'' The National Ski Area Association's regional listings of participating areas are available for $4.95 by phoning 800-638-8976.