Story was updated at 10:45 a.m. as airline shares rose.

A not-well-contained fare war, two hurricanes and higher fuel prices have challenged airline share prices since July, but the worst may be over.

On Friday, Sept. 8, at the end of a week when four carriers reduced third-quarter unit revenue guidance, shares in most airlines rose, led by JetBlue Airways Corp. (JBLU) and Spirit Airlines Inc. (SAVE) , both up 2.4%.

During the week, Delta Air Lines Inc (DAL) , Southwest Airlines Co. (LUV) , United Continental Holdings Inc. (UAL) and Spirit all cut unit revenue guidance; all but Delta cited the impact of Hurricane Harvey as a factor. Hurricane Irma will also impact the industry, given thousands of flight cancellations in Florida over the weekend.

Since July 7, when it reached an all-time high, the Standard and Poor's Composite Airlines Index has fallen 18%. Of the eight major airlines, only Southwest has a year-to-date share price gain, with shares are up 6%.

In morning trading Monday, shares in every major airline were up. American Airlines Group Inc. shares, Delta shares and JetBlue shares were up 3%, while United was up 2%.

Irma's impact was less than expected. Also, a few encouraging signs emerged last week.

At the Cowen & Co. investor conference on Wednesday, Sept. 6, both American Airlines Group Inc (AAL)  and Delta were, in the words of Cowen analyst Helane Becker, "more incrementally positive about the prospects of a recovery in 4Q as leisure demand remains strong."

Becker's comments, in a report, came after Don Casey, American's senior vice president of revenue management, told the conference, "As we went through July and August, we're on track with our guidance, but there is a lot of uncertainty facing us in September, particularly with Hurricane Irma," while Delta Chief Financial Officer Paul Jacobsen said Delta's reduced margin guidance reduction primarily reflected higher fuel costs.

"Advance yields for fourth quarter are coming in nicely," Jacobsen told the conference. "It's too early to call the fourth quarter, {but} we feel good about the trend lines we're on -- leisure is strong.

"The industry is performing better than it ever has been, [but] it's sometimes hard to see the forest for the trees," he said. "We're doing very well -- that's in spite of low-cost-carrier growth and ultra-low-cost-carrier growth."

On Thursday, Sept. 7, after meetings with airline managements, Deutsche Bank analyst Mike Linenberg wrote that "Delta and American both noted that they expected to see positive Dec quarter unit revenue, a topic which has been top of mind for investors trying to find a bottom for the stocks."

"Most [managements] seemed to agree that recently fares have stabilized at the lower end of the fare structure possibly driven by the recent uptick in fuel prices and management's desire to minimize margin degradation," Linenberg said.

"The biggest risk for the stocks, in our view, is that the competitive fare actions between Spirit and United spread to other major markets," he said.

United had a tough week, losing 5%. But United said it resumed a full schedule in Houston more quickly than it had expected. The carrier also announced it will begin Houston-Sydney service in January.

Year to date, Spirit shares are down 43%; Hawaiian Holdings Inc. has fallen 31%; Alaska Air Group Inc. has declined 16%: United is down 20% and JetBlue is down 11%. American is down 7% and Delta is down 4%.

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This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.

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