Southwest Airlines (LUV), known for its discount fares and not charging for two carry-on bags, said Friday it would raise current fees and implement new ones to help boost revenue by $1.1 billion next year. At the company's investor day, Southwest said it will raise fees on third bags and overweight baggage, but passengers' first two bags will still be free. Fares on AirTran, the budget carrier it bought last year, will be raised and passengers