Texas Air Corp., which owns Continental and Eastern Airlines, has run into a patch of rough weather recently that sent its stock price diving.

The company that has led the industry in consolidations and cost-cutting, in recent months has also been an industry leader in passenger complaints, reflecting the difficulties in making its merger of People Express, New York Air and Frontier Airlines into Continental and uneasy labor relations at Eastern.

Airline industry analysts began reducing estimates for third-quarter earnings for the company recently in recognition of the merger-related difficulties. The stock, which reached a peak of $51.50 earlier this year, dropped from $31.62 1/2 on Aug. 31 to $25.75 on Tuesday. Yesterday the stock closed at $26.75, up $1

"I had way too high expectations for them. I think they had too high expectations for themselves," said David Sylvester, an industry analyst with Kidder, Peabody & Co. Inc. Sylvester said he had been forecasting $2.40 a share in profits. "Now I'm down to a dollar, and if they make money I'll feel good."

Airline industry stocks in general have been depressed recently. Investors "are concerned that some significant reregulation may be enacted next year, and they're concerned about what's going to happen in the Mideast" because increased oil prices might raise airline costs and reduce earnings, said Paul P. Karos, an analyst with L.F. Rothschild, Unterberg, Towbin, Inc.

In Texas Air's case, the reaction has been compounded by Continental's difficulties in digesting other airlines. The company has blamed those difficulties for its ranking in recent Department of Transportation consumer complaint reports. In June and July, Continental led domestic airlines in the number of complaints per 100,000 passengers. Last month, Continental dropped down to number two in the rankings behind Northwest Airlines.

Continental officials have protested that the DOT ratings are an unscientific sample based on consumer-initiated complaints and have blamed airline unions for some of the complaints but have conceded that the merger of the four carriers in February created greater problems than anticipated.

Last month Continental announced that it will move into a new, more efficient terminal at Newark International Airport, which has been a major center of operational difficulties.

In the long run, according to analysts and Texas Air officials, earnings are likely to improve. "Nothing has changed that would take away the earning power of Continental's assets. It's just that integrating those assets in 1987 proved to be very difficult," said Sylvester.

Nonetheless, there are some tests ahead for Texas Air. The Air Line Pilots Association has begun an organizing campaign at Continental, which shed its unions as the result of a bankruptcy reorganization filing in 1983 and became a low-cost airline in large part by reducing wages and eliminating benefits.

Continental spokesman Bruce Hicks said that the airline is confident that pilots will reject the union's overtures, noting that the pilots voted about two years ago not to retain ALPA as their bargaining representative. The union, which has had to contend with wage-cutting at other airlines pressured by competition from Continental, is expected to mount a major effort there, however.

Eastern is also facing potential labor problems. Labor-management relations have deteriorated there since Texas Air's acquisition of the airline, and Texas Air has announced plans to cut Eastern's labor costs by $490 million.

The first contract subject to renegotiation under the Lorenzo regime is the contract covering machinists and other employes represented by the International Association of Machinists and Aerospace Workers. "There's been some evidence that the company perhaps wanted to normalize labor relations from the warfare that has been going on, but there has not been any really significant development in that respect," said Charles E. Bryan, president of the IAM local that represents 13,000 workers at Eastern.

Bryan, a pivotal figure in Eastern's recent history who traded inevitable concessions for an employe stake in the airline under its previous ownership, said he expects negotiations to be tough. Bargaining is expected to begin Oct. 2 with an initial exchange of proposals. "They're talking in terms of trying to reduce Eastern wages to Continental levels. If they're locked into that mode, it's certaining going to be a difficult time," he said.

Eastern pilots, whose contract is not negotiable until Dec. 31, meantime have been emphasizing what they call a safety campaign, delaying flights to make sure that maintenance is properly done. Pilots are quitting the airline and moving to other carriers, said pilot spokesman J.B. Stokes. "When you lose over 10 percent of your pilot force, that's a fairly serious condemnation of your business," he said.

Eastern said that 374 pilots left the airline either because of resignations, terminations, death or retirement in the first eight months of 1987. In contrast, during the first eight months of 1986, only 119 pilots left.