Texas Air Corp. Chairman Frank Lorenzo says the company's troubled Eastern Airlines subsidiary must be restructured to ensure its financial recovery.

Despite persistent labor agitation and financial troubles at the Miami-based airline, Lorenzo told Texas Air shareholders Thursday at the annual meeting that "Eastern Airlines is not for sale.""We have many, many loyal customers," Lorenzo said. "We are committed to providing a full-value product."

Lorenzo said a study completed recently by Texas Air shows that the airline has a net-asset value, taking into account debts and liabilities, of $2 billion, or nearly $50 per Texas Air share.

He said Texas Air management is looking at actions to improve value to shareholders but declined to specify what actions are under consideration.

In a news conference following the meeting, Lorenzo said that the current price of Texas Air shares is "very low and unacceptable."

Eastern President Phil Bakes told shareholders, "Eastern just be restructured and positioned for future profitability."

He said Eastern management has cut about $200 million in annual costs and is "striving mightily" to resolve its problems with its unions.

Eastern and Texas Air recently sued the pilots and machinists unions at Eastern for $1.5 billion, accusing them of "Eastern bashing" and trying to drive down the value of the company. Eastern recently announced layoffs of several thousand employees.

Lorenzo said management was also looking at ways to improve liquidity at Eastern and at Continental Airlines, Texas Air's other main subsidiary. He said the company's management is focusing attention on turning Eastern and Continental into profitable operations.

Together, the Texas Air carriers have a staggering debt of around $5.4 billion. The parent company posted a record net loss of $466 million in 1987.

Lorenzo presided over an often tense but generally controlled shareholder meeting, threatening several times to have security guards eject shareholders and union members who continued their questioning after he had asked them to refrain.

Lorenzo was flush from a victory earlier this week, when an appeals court in Washington lifted a ban on the sale of Eastern's Northeast shuttle operations to another subsidiary of Texas Air.

And last Thursday, the Federal Aviation Administration concluded after a two-month safety investigation of Texas Air, Eastern and Continental that they are safe to fly.

The FAA said, however, that the bitter labor-management war at Eastern raises possible safety risks if allowed to continue. The agency said it will continue its surveillance of Eastern.

Continental President Martin Shu-grue said he was "pleased, but not surprised" that the FAA had given Continental a clean safety bill of health. He said Continental was making substantial investments to improve its financial performance.

"We've now completed the most complex integration in the history of the airline industry," Shugrue said. Houston-based Continental is itself the parent of Frontier Airlines, People Express and New York Air. All three have ceased operating.