LOS ANGELES (Reuters) - Air America has shut its sales offices in Los Angeles and Chicago and is recasting its business plan, the network's president said on Wednesday as troubles beset the liberal talk show network. With Air America not broadcasting in those two cities after a financial dispute in April, network president Jon Sinton said, "There's not much sense in having sales offices in cities where you don't control a station." About 15 to 20 people were laid off in the closing of the sales offices, the latest sign of problems for Air America, launched on March 31...