Momentum investing is essentially the opposite of the tried-and-tested Wall Street adage -- "buy low and sell high." Investors following this investing style typically avoid betting on cheap stocks and waiting long for them to recover. They believe instead that one could make far more money in lesser time by "buying high and selling higher."

Who doesn't like betting on fast-moving trending stocks? But determining the right entry point isn't easy. Often, these stocks lose momentum once their valuation moves ahead of their future growth potential. In such a situation, investors find themselves loaded up on expensive shares with limited to no upside or even a downside. So, going all-in on momentum could be risky at times.

It could be safer to invest in bargain stocks that have been witnessing price momentum recently. While the Zacks Momentum Style Score (part of the Zacks Style Scores system), which pays close attention to trends in a stock's price or earnings, is pretty useful in identifying great momentum stocks, our 'Fast-Paced Momentum at a Bargain' screen comes handy in spotting fast-moving stocks that are still attractively priced.

United Airlines (UAL) is one of the several great candidates that made it through the screen. While there are numerous reasons why this stock is a great choice, here are the most vital ones:

A dash of recent price momentum reflects growing interest of investors in a stock. With a four-week price change of 5.3%, the stock of this airline is certainly well-positioned in this regard.

While any stock can see a spike in price for a short period, it takes a real momentum player to deliver positive returns for a longer time frame. UAL meets this criterion too, as the stock gained 82.5% over the past 12 weeks.

Moreover, the momentum for UAL is fast paced, as the stock currently has a beta of 1.44. This indicates that the stock moves 44% higher than the market in either direction.

Given this price performance, it is no surprise that UAL has a Momentum Score of A, which indicates that this is the right time to enter the stock to take advantage of the momentum with the highest probability of success.

In addition to a favorable Momentum Score, an upward trend in earnings estimate revisions has helped UAL earn a Zacks Rank #1 (Strong Buy). Our research shows that the momentum-effect is quite strong among Zacks Rank #1 and #2 stocks. That's because as covering analysts raise their earnings estimates for a stock, more and more investors take an interest in it, helping its price race to keep up. You can see the complete list of today's Zacks Rank #1 (Strong Buy) stocks here >>>>