With just a few days before Christmas weekend, U.S. holiday travelers are seeing spikes at the gas pump because of higher oil prices, a retail analyst said. Motor club AAA in its weekly retail market report already noted the price at the pump has increased almost every day for the last three weeks. It lists a national average retail price for a gallon of regular unleaded gasoline at $2.25 per gallon. Some of the more volatile markets in the United States like the Great Lakes states are seeing prices soar, with Michigan gas prices moving up 4 percent, or 8 cents per gallon, overnight. Separate analysis from price-watcher GasBuddy found the national retail price for gasoline has posted its largest increase for December since the start of the decade and that could in turn put a damper on consumer pocketbooks moving into Christmas weekend. […]