The proven Zacks Rank system focuses on earnings estimates and estimate revisions to find winning stocks. Nevertheless, we know that our readers all have their own perspectives, so we are always looking at the latest trends in value, growth, and momentum to find strong picks.

Of these, perhaps no stock market trend is more popular than value investing, which is a strategy that has proven to be successful in all sorts of market environments. Value investors rely on traditional forms of analysis on key valuation metrics to find stocks that they believe are undervalued, leaving room for profits.

Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.

One company to watch right now is Deutsche Lufthansa (DLAKY). DLAKY is currently sporting a Zacks Rank of #2 (Buy), as well as a Value grade of A. The stock holds a P/E ratio of 4.86, while its industry has an average P/E of 10.02. Over the past 52 weeks, DLAKY's Forward P/E has been as high as 20.05 and as low as 4.14, with a median of 5.46.

We also note that DLAKY holds a PEG ratio of 0.22. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. DLAKY's industry currently sports an average PEG of 0.50. Over the last 12 months, DLAKY's PEG has been as high as 0.24 and as low as 0.16, with a median of 0.19.

Value investors also frequently use the P/S ratio. This metric is found by dividing a stock's price with the company's revenue. This is a prefered metric because revenue can't really be manipulated, so sales are often a truer performance indicator. DLAKY has a P/S ratio of 0.26. This compares to its industry's average P/S of 0.42.

Finally, investors will want to recognize that DLAKY has a P/CF ratio of 2.03. This metric focuses on a firm's operating cash flow and is often used to find stocks that are undervalued based on the strength of their cash outlook. DLAKY's current P/CF looks attractive when compared to its industry's average P/CF of 5.93. DLAKY's P/CF has been as high as 4.03 and as low as 1.71, with a median of 2.70, all within the past year.

If you're looking for another solid Transportation - Airline value stock, take a look at Controladora Vuela Compania de Aviacion, B. de C.V. (VLRS). VLRS is a # 2 (Buy) stock with a Value score of A.