Holiday Travel Season Expected to Be Busiest in Six Years And a new report out today warns of holiday gridlock. Abc's senior national correspondent jim avila tells us how to navigate around it. Reporter: Planes are full, and that means even higher prices for holiday travel. A new report from the airline trade group released today shows demand strong and planes flying at 85% to 90% capacity. Non-stop ticket prices christmas week are nearly double what they were at the beginning of the month. And rising by the day. Every day you wait for your virtual airline ticket, add about $7 to $8 for each day that you wait. Reporter: The average domestic air fare is now $414 according to travelocity -- a 9% jump over last year's holiday season. The most expensive days to fly? Up to $500 more a ticket are DECEMBER 21st, 22nd AND ON THE RETURN, DECEMBER 30th, 31st AND New year's day. These are the cheaper days to fly -- christmas day and the three days after. Flying then can save as much as $330. You're going to sacrifice price for convenience, but you'll also encounter fewer crowds at the airport. Reporter: And it's not just air fares that are making this a profitable season for airlines. If you're checking bags, make sure they're not overweight by using a home scale. Airlines charge excessive baggage surcharges that start at $90 on top of the now normal baggage fee. And the scales at the airport are not always accurate. It said 50 pounds when i first put it on. Now it says 47. Reporter: An abc news investigation last year at this time showed 5% of airport scales checked nationwide were off in one direction or another, by at least half an ounce -- enough to add costs. Adding injury to the already insulting high holiday fares. Jim avila, abc news, n