shares of united airlines holdings inc ual inched 006 higher to 4791 thursday on what proved to be an allaround great trading session for the stock market with the sp 500 index spx rising 171 to 443826 and the dow jones industrial average djia rising 156 to 3491256 united airlines holdings inc closed 1579 below its 52week high 6370 which the company achieved on march 18th the stock underperformed when compared to some of its competitors thursday as southwest airlines co luv rose 051 to 5151