The number of Americans traveling 50 miles or more from home will drop 1.9 percent, from 37.8 million last year to 37.1 million this year, AAA said.
"Many Americans remain cautious about the outlook for their personal finances, and these attitudes are reflected in the slight decline in travel we are forecasting for the upcoming holiday weekend," Robert L. Darbelnet, AAA president and chief executive officer, said in a statement.
Air trips will account for just 5 percent of leisure travel, AAA said, but the airline industry is expected to see a 4.9 percent increase in leisure bookings because of declining fares and pent-up demand among travelers who have put off plane trips.
Gas price increases and lower air fares will reduce the number of auto trips by 2.6 percent, to 32.6 million, AAA said.
Fourth of July weekend travelers expect to spend about $1,160 per household, with transportation and accommodations accounting for half of that, AAA said.
AAA based its projections on research conducted by IHG Global Insight, an economic research and consulting firm in Boston.