While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of American Airlines Group, Inc. (NASDAQ:AAL) gained about 1% in premarket trading Monday after Goldman Sachs initiated coverage on the airline operator with a buy rating.

So what: Along with the bullish call, analyst Tom Kim planted a price target of $46 on the stock, representing about 26% worth of upside to Friday's close. So while contrarians might be turned off by American Airlines' price spike over the past several months, Kim's call could reflect a strengthening sense on Wall Street that its turnaround potential still isn't fully baked into the valuation.

Now what: Goldman's 2014 and 2015 estimate for American Airlines is about 7% and 11.5%, respectively, above Wall Street's view. "The carrier's margins are poised to expand 2.0 ppts over 2013-16E to 12.7%, which we expect to drive multiple expansion," said Kim. "Meanwhile, earnings growth should accelerate thanks to a favorable airline cycle, which we expect to facilitate AAL's integration initiatives more than the market anticipates. Consensus upgrades should catalyze near-term share performance while margin growth drives multiple expansion, in our view." Of course, when you couple the airline industry's notoriously intense nature with the stock's red-hot run-up, American Airlines' long-term risk to reward trade-off doesn't seem as attractive.

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Brian Pacampara has no position in any stocks mentioned. The Motley Fool recommends Goldman Sachs. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.