Since big mutual fund firms like Fidelity and Vanguard own pretty much everything, it's not surprising that they're major investors in the notoriously unrewarding airline industry.

However, there are also a few less likely names on the lists of the biggest shareholders at the major U.S. airlines.

For instance, hedge fund manager Jeffrey Gendell is among the biggest investors in

AMR

(AMR)

, parent of American Airlines. The federal government's Pension Benefit Guaranty Corp. is among the biggest stockholders in

UAL

(UAUA)

, the owner of United Airlines.

At the moment, soaring prices for airline stocks make recent investments in the sector look pretty good. The Amex Airline Index has risen more than 40% since its low point in late September.

Longer term, the story hasn't been nearly as bright. Since the Wright Brothers first flew, the industry has lost more than $25 billion, according to the industry's trade group, the Air Transport Association.

Through filings with the

Securities and Exchange Commission

, Gendell reported that he and his Greenwich, Conn., firm, Tontine Associates, owned 11.7 million shares of AMR, or 6.3% of the company, following purchases on Aug. 31 and Dec. 31. The stock has nearly tripled since trading at $10 a share during the day on Sept. 22.

Of course, it started a long climb from $1.25 a share in March 2003. Gendell didn't return phone calls from

TheStreet.com

, and AMR declined to comment.

The PBGC, meanwhile, acquired shares in UAL as collateral when the airline defaulted on its pension plan during its bankruptcy. The agency will hold 10% to 12% of the airline once stock is fully distributed to the unsecured creditors, said PBGC spokesman Jeffrey Speicher.

By holding UAL's stock, the agency is in an uncommon position. "The vast majority of the pension plans that come to the PBGC come in the context of a liquidation, not in the context of reorganization," Speicher said. "The UAL position is not typical."

The PBGC said in an SEC filing that it received 11.1 million shares of the airline in February in recognition of its unsecured pension claims. With UAL's shares closing Friday at $38.82, the PBGCs' holdings are worth more than $400 million.

Despite the industry's recent strong performance, Morningstar airline analyst Chris Lozier thinks mutual funds should be careful about airline investing, which is historically unprofitable.

"With this industry, you know it's cyclical," Lozier said. "Even if the stocks are good now, they're not going to be that way always, and they could potentially be significantly worse. Short-term gains can be had, but I don't know if there is a tried and true way of determining what moves these stocks over a short period."

Still, Lozier acknowledged that in the cases of the biggest institutional investors, "when you get to a certain size, you run out of places to put money."

Vanguard spokesman Michael Smith said that, overall, about half of the group's holdings are determined by index fund purchases, while half are decided by active fund managers.

Among the seven largest airlines,

Delta Air Lines

(DALRQ)

and

Northwest Airlines

(NWACQ)

are operating under bankruptcy court protection. Major investors in United, which recently emerged from bankruptcy, have not yet reported their holdings.

At AMR, the top seven shareholders include Primecap Management and Wellington Management. Combined, they own nearly 15% of the shares, as reported on Dec. 31. Fidelity owns 7%, while Ameriprise Financial and Oppenheimer Funds each own nearly 5%. The hedge fund Trafelet & Co. holds 4.4%.

At

Continental Airlines

(CAL) - Get Report

, Oppenheimer Funds and Wellington each own about 11%. Mellon Financial, Dimensional Fund Advisors and Allianz Global Investors of America each have about 5%, according to the available data.

For

Southwest Airlines

(LUV) - Get Report

, Capital Research & Management, the manager of the American funds, holds 9.8%, Wellington owns 5.4%, and Vanguard 2%. Primecap, Barclays Global Investors, T. Rowe Price and Fidelity each owned about 4% at the end of last year.

Meanwhile, Wellington owns nearly 17% of

US Airways

(LCC)

, while Fidelity and Par Capital Management each own about 16%. Tudor Investment Corp. has 7%, Peninsula Capital Advisors nearly 6% and Trafelet & Co. about 4%. The data reflect holdings as of Dec. 31.