You won't believe how this sector's doing

Could airlines finally be an investable sector? If 2014 results are any indication, the answer is yes.

Once considered by investors as merely a proxy for oil, airlines are up 23 percent so far this year. And the gains have been broad-based. In fact, some of the largest publicly traded airlines in the U.S. are flying high this year.

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Airline Ticker Market cap ($ bln) 2014 ytd returns 12 month returns
Delta DAL $28.6 21% 123%
American AAL $16.6 41% N/A
United Continental UAL $16.2 14% 44%
Southwest LUV $16.1 24% 81%
Alaska Air ALK $6.1 23% 50%
Spirit SAVE $4.0 23% 120%
JetBlue JBLU $2.6 2% 30%

So what changed? Why has this notoriously fickle sector suddenly become so hot, and how long can the gains last? According to CNBC contributor Gina Sanchez, founder of Chantico Global, the airline industry has changed from the days when it was considered the market's biggest wealth destroyer.

Sanchez sees three reasons why airlines have turned themselves around: lower fuel prices, industry consolidation and improved balance sheet health.

"I don't think this trade is over," said Sanchez. But, she sees the size of the airline as mattering for investors, particularly those buying a related index or exchange-traded fund (ETF).

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"You have to be aware of the different exposures to airline industries and look at the weighting schemes," said Sanchez. "Be aware that right now, probably owning the smaller caps isn't such a great thing. So, an equal-weighted scheme really isn't going to work for you—just know your ETF."

However, Talking Numbers contributor Richard Ross, global technical strategist at Auerbach Grayson, doesn't think investors should board the airlines.

"I think the move is most of the way over," said Ross. "Chasing a group as notorious as the airlines at the tail end of a multiyear, triple-digit move is not exactly a strong play in my opinion."

Ross does see strength in the near-term chart of the NYSE ARCA Airlines Index, an equal dollar weighted index comprised of airlines in both the U.S. and the rest of the world. But, while the index has rebounded over the past dozen years and could potentially go a little higher from here, Ross would not buy it.

"There's a lot of momentum here," said Ross. "But, if you've missed the ride, I wouldn't want to chase it here. That, for me, is not the play to make."

To see the full discussion on airlines, with Sanchez on the fundamentals and Ross on the technicals, watch the video above.

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