United Airlines (UAL) , a prominent Chicago-based airline, has seen its shares decline 16.5% over the past three months compared to its industry's 1.7% rise during the same period. The S&P 500 composite index rose 6.5% in the same time frame, while the Zacks Transportation sector gained 22.6%. The company currently has a market capitalization of $14.48 billion. Image Source: Zacks Investment Research Factors Impeding UAL's Growth United Airlines has been struggling on the revenue front of late due to overca ...