(FORTUNE Magazine) – Vacationers planning to holiday in the U.S. this summer will probably do best on air fares by booking at the last minute. A small price skirmish has broken out now that America West Airlines has cut fares by up to 40% on some domestic flights. But don't expect a big-scale fare war right away. Says Lee Howard, president of Airline Economics, a Washington, D.C., research firm: ''Airlines will hold fast until they are certain they can't put people in the seats at profitable rates.'' Meanwhile, Alaska has become a hot spot for summer cruises, in part because Americans still have jitters about overseas travel. Holland America Line Westours, Princess Cruises, and ten other companies offer 332 five-day to two- week voyages, 10% more than last year. Prices range from less than $1,000 to $11,400. Air fares are sometimes extra. K.B.