NEW YORK (TheStreet) -- Shares of American Airlines (AAL) - Get Report are flying lower Tuesday after Cowen & Co. downgraded the stock to hold from buy. But on CNBC's "Mad Dash" segment, TheStreet's Jim Cramer said investors shouldn't be so fast to sell the stock. 

Shares are "so unbelievably cheap" right now that investors ought to think twice before selling, said Cramer, the co-manager of the Action Alerts PLUS portfolio. Shares are currently trading around $50.

The stock has been "resting" now that oil prices have started to stabilize, he pointed out. His favorite stock in the industry remains Spirit Airlines (SAVE) - Get Report , he said. 


First Solar FSLR and American Airlines AAL data by YCharts

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Sticking to energy, Cramer said First Solar (FSLR) - Get Report announced "some really positive news" -- plans to start a "YieldCo" venture with SunPower (SPWR) - Get Report . Shares of First Solar were up 15% on the news. 

A lot of analysts bailed First Solar but now they'll be scrambling to upgrade their ratings on the news. Both companies will contribute different assets to YieldCo before taking the newly formed entity public once the deal is complete. 

YieldCos tend to have more predictable cash flows and distribute most of their earnings in the form of dividends, Cramer said. They are structured similarly to a real estate investment trust or master limited partnership. 

It will basically be like utility bonds, Cramer said, adding that the move also increases First Solar's access to lower capital costs. First Solar is scheduled to report its earnings after the closing bell on Tuesday.

-- Written by Bret Kenwell

Follow @BretKenwell

At the time of publication, Cramer's Action Alerts PLUS had no position in companies mentioned.