yesterdayreported stronger July-September results as crowded jets more than compensated for lower average fares.

The results reflect a combination of the growing economy and airline efforts to cut costs and reduce fleets. That has helped fill seats and produce some surprisingly big profits at a number of airlines. The domestic airline industry has lost $12.8 billion over the previous four years.

Low jet fuel prices also helped in the latest quarter, but that benefit will be erased next year when a 4.3-cent per gallon tax takes effect.

UAL Corp. reported a 45 percent profit drop, but the earnings were driven down by $96 million in costs associated with the employee acquisition of the airline. Delta's profit rose 18 percent if a one-time gain from an accounting change is excluded.

UAL earned $82 million, or $4.24 per share, on revenues of $3.8 billion in the three months ended Sept. 30. In the same period a year earlier, UAL had a profit of $149 million, or $5.74 per share, on revenues of $3.6 billion.

United employees, led by pilots and ground-crew workers, bought a majority stake in the airline earlier this year in a bid to ensure labor peace as it undergoes a restructuring to compete against cheaper carriers.

The company said profit would have been $178 million in the latest quarter without the buyout expenses.

In the first nine months of the year, earnings were $40 million, or 3 cents per share, on sales of $10.5 billion. Last year's nine month figure showed a loss of $15 million, or 38 cents per share, on revenues of $9.98 billion.

Delta earned $186 million, or $3.25 per share, on revenues of $3.16 billion in the quarter, the first in its fiscal year. A year ago the company had a profit of $61 million, or 65 cents per share, on sales of $3.14 billion.

Not counting the $114 million accounting change benefit, the company earned $72 million, or $1 per share, in this year's quarter.

Delta said its trans-Atlantic division made money in the quarter for the first time since it bought many of Pan Am's old routes in 1991.

In the first nine months of 1994, Delta lost $142 million.