UAL Inc., the parent company of United Airlines and the nation's second largest transportation company, yesterday reported troubled airline profits during the third quarter and blamed reduced passenger traffic and high fuel costs for much of that.

Meanwhile Pan American World Airways Inc. said its third-quarter profits dropped 59.7 percent, and Delta Airlines said its third-quarter earnings were almost double those of a year ago.

UAL, which is based in Chicago, reported net earnings of $1.05 million (3 cents a share) on revenues of $1.345 billion for the quarter. But company officials said the earnings were due wholly to the ability of its nonairline operations to overcome a $9.7 million loss reported by the airline.

The latest profit represents an imrpovement from the 1979 third-quarter loss of $15.8 million (54 cents) on revenue of $1.2 billion.

UAL reported a nine-month loss of $14.5 million (50 cents) on revenues of $3.74 billion. In the 1979 period UAL had a net loss of $60.26 million ($2.08) on revenue of $2.64 million.

Pan Am said its third-quarter earnings were $24.5 million (34 cents a share) on sales of $1.02 billion. A year ago, third-quarter earnings came to $60.8 million (86 cents) on sales of $741.1 million.

The company also posted nine-month losses of $116.7 million on sales of $2.69 billon. A year earlier, Pan Am earned $89 million ($1.25) on sales of $1.85 billion over nine months.

Delta said it earned $26.3 million ($1.31 a share) in the third quarter compared with $12.6 million (63 cents) a year earlier.

Operating revenues grew 25 percent to $838.2 million, while operating expenses rose 20 percent to $801.5 million.

Nine-month net income was $85.8 million ($4.32), up 4 percent from the $82.6 million earned in the same period last year.