Impact of gasoline prices on travel plansAAA estimates the national average price of gasoline will drop to between $3.25-3.40 a gallon by the holiday, similar to last year's average of $3.32, which was the most expensive average ever on Thanksgiving. Despite the historically high prices paid by motorists this year, the national average has declined by nearly 40 cents a gallon since early October and should continue to drop through the end of the year. The national average price of gas for Thanksgiving from 2007-2011 is $2.75 a gallon.Wednesday before the holiday is expected to be busiest travel dayThe Thanksgiving holiday is unique falling on a Thursday every year. Many people are off from work the Friday after, giving travelers the opportunity to spend more time with family and friends. AAA asked intended travelers which days they would depart for and return from Thanksgiving Travel. Among those surveyed, the majority of travelers plan to leave the Wednesday before the holiday (45 percent) and return the following Sunday (36 percent) with another 25 percent expecting to return on Monday, Nov. 26. Automobile travel remains dominant mode of transportation, air travel decreasesApproximately 90 percent of travelers or 39.1 million people plan to travel by automobile this Thanksgiving. This is a 0.6 percent increase over the 38.9 million people who traveled by auto last year. Air travel is expected to decrease 1.7 percent as 3.14 million holiday travelers will take to the skies. Those traveling by air will find lower airfares according to AAA's Leisure travel Index. For the Thanksgiving holiday the average lowest round-trip rate is $188 for the top 40 U.S. air routes, an 11 percent decrease from last year. Approximately 1.3 million travelers will choose other modes of transportation, including rail, bus and cruise ship. Hotel rates relatively flat, car rental rates increase 27 percentAccording to AAA's Leisure Travel Index, Thanksgiving holiday hotel rates for AAA Three Diamond lodgings are expected to decrease one percent from a year ago, with travelers spending an average of $143 per night compared to $145 last year. Travelers planning to stay at AAA Two Diamond hotels can expect to pay one percent more, at an average cost of $104 per night. Weekend daily car rental rates will average $47, compared to $37 last year.