Right now, General Dynamics Inc. (NYSE:GD) share price is at $160.88, after a 1.58% drop. Over the past month, the stock increased by 22.34%, but over the past year, it actually decreased by 6.44%. With questionable short-term performance like this, and great long-term performance, long-term shareholders might want to start looking into the company's price-to-earnings ratio.

The stock is currently above from its 52 week low by 60.00%. Assuming that all other factors are held constant, this could present itself as an opportunity for investors trying to diversify their portfolio with Aerospace & Defense stocks, and capitalize on the lower share price observed over the year.

Most often, an industry will prevail in a particular phase of a business cycle, than other industries.

General Dynamics Inc. has a lower P/E than the aggregate P/E of 41.05 of the Aerospace & Defense industry. Ideally, one might believe that they might perform worse than its peers, but it’s also probable that the stock is undervalued.

Price to earnings ratio is not always a great indicator of the company's performance. Depending on the earnings makeup of a company, investors may not be able to attain key insights from trailing earnings.