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 value investors might notice is Allegiant (ALGT). ALGT is currently sporting a Zacks Rank of #2 (Buy), as well as an A grade for Value. The stock holds a P/E ratio of 12.58, while its industry has an average P/E of 18.67. ALGT's Forward P/E has been as high as 12.70 and as low as 5.77, with a median of 9.57, all within the past year.

ALGT is also sporting a PEG ratio of 1.04. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. ALGT's industry has an average PEG of 1.09 right now. ALGT's PEG has been as high as 1.54 and as low as 0.68, with a median of 0.93, all within the past year.

Investors could also keep in mind Controladora Vuela Compania de Aviacion, B. de C.V. (VLRS), an Transportation - Airline stock with a Zacks Rank of # 2 (Buy) and Value grade of A.

Shares of Controladora Vuela Compania de Aviacion, B. de C.V. currently holds a Forward P/E ratio of 10.94, and its PEG ratio is -2.17. In comparison, its industry sports average P/E and PEG ratios of 18.67 and 1.09.

VLRS's Forward P/E has been as high as 6,243.17 and as low as -73,021.84, with a median of 10.39. During the same time period, its PEG ratio has been as high as 644.96, as low as -7,543.58, with a median of -1.97.

Controladora Vuela Compania de Aviacion, B. de C.V. also has a P/B ratio of 2.82 compared to its industry's price-to-book ratio of 4.98. Over the past year, its P/B ratio has been as high as 6.43, as low as 2.19, with a median of 3.45.

These are just a handful of the figures considered in Allegiant and Controladora Vuela Compania de Aviacion, B. de C.V.'s great Value grade. Still, they help show that the stock is likely being undervalued at the moment. Add this to the strength of its earnings outlook, and we can clearly see that ALGT and VLRS is an impressive value stock right now.