Southwest Airlines and American Airlines raised their fourth-quarter forecasts on Thursday, citing strong demand and higher fares, sending shares in the carriers higher.Southwest said fourth-quarter unit revenue will likely rise between 5.5% and 7% from last year, up from a previous forecast of an increase of no more than 5.5%. The airline said its network changes aimed at culling unprofitable flights are paying off and that demand into next year appears solid."The Company is encouraged by recent revenue tr ...