Thanks to still-surgins Jeep sales, American Motors Corp. reported its best first-quarter profits ever yesterday of $26.2 million (86 cents a share).

AMC's ninth consecutive quarter in the black reflected a 28 percent jump in sales to a record $715 million for the three months ended Dec. 31.

The first-quarter results compare to slim earnings of $1.9 million (six cents) for the same quarter a year ago, on sales of $559 million.

The results were "substantially better than I expected," said auto analyst Arvid Jouppi of John Muri & Co., a New York investment banking and securities firm.

(Meanwhile, Automotive News reported that AMC will offer front wheel drive as an option in 1980 models of its Concord compact passenger car.)

(The automaker would not confirm or deny the trade publication's report, which also said AMC would buy the systems from Chrysler Corp. because four-wheel-drive systems in AMC Jeeps aren't the right size.)

National Airlines' net income reached $18.3 million in 1978 -- the highest level in four years -- due mainly to record passenger loads, officials said yesterday.

The firm said the annual earnings equaled $2.14 a share compared to 75 cents in 1977, when earnings totaled $6.4 million. Operating revenues were a record $630 million, up $17 million over the 1977 figure.

For the quarter ended Dec. 31, net income was $2.8 million (33 cents) compared with $1.7 million (20 cents) in 1977. Quarterly revenues were $155 million against $139 million in the same period last year.

National remains the targe of a contentious, three-way takeover battle waged by Pan American World Airways, Eastern Airlines and Texas International Airlines. The Civil Aeronautics Board is expected to rule by March on which of those airlines -- if any -- may seek operating control of National.

RCA Corp. said yesterday that better results in all areas of the company's operations but broadcasting contributed to record financial results in 1978.

Annual earnings for the giant communications conglomerate were $278.4 million ($3.65 a share), up from $247 million ($3.23) in 1977. Sales rose from $5.92 billion to $6.65 billion.

Fourth-quarter results also set records. Earnings in the quarter were $75.2 million (99 cents) compared with $65.5 million (86 cents) a year earlier. Slaes rose to $1.85 billion from $1.66 billion.

The company said only NBC broadcasting failed to show an improvement in earnings, although it did turn a profit.

Aluminum Co. of America reported 1973 net income of $312.7 million ($8.90 a share) compared with $195.2 million ($5.58) a year earlier and increased its dividend from 50 cents to 60 cents.

Sales and operating revenues were $4.1 billion in 1978 compared with $3.4 billion in 1977. The quarterly dividend, up for the third straight year, is payable Feb. 25 to shareholders of record Feb. 2.

Aluminum product shipment were 1.77 million tons in 1978 compared with 1.68 million tons the previous year.

Fourth-quarter profits rose from $44.8 million ($1.27) in 1977 to $100.3 million ($2.85) as sales increased from $831.4 million to $1.09 billion

Westinghouse Electric Corp. announced 1978 net income of $256.4 million ($2.96 a share) slightly higher than 1977 net income of $250.7 million, ($2.86). Sales for 1978 amounted to $6.88 billion compared with 1977 sales of $6.13 billion.

Westinghouse Chairman Robert E. Kirby said the company's uraniumsupply lawsuit resulted in a loss of $54.7 million in 1978 net income. He said the loss does not include the effect of the uranium settlement agreements with two Swedish utilities expected to become final on Feb. 9. The agreements are subject to approval by the utility boards and Westinghouse.

In the fourth quarter, Westinghouse earned $88.1 million ($1.02) on sales of $1.78 billion. The 1977 fourth-quarter earnings were $61.04 million (70 cents) on sales of $1.66 billion.

Westinghouse also said separately that it will build the first commercial version of a new type of electric generator designed to be cheaper, smaller and more efficient than conventional models.

The superconducting generator utilizes metal at a temperature of 452 degrees below zero. Very cold metal has almost no resistance to electricity.

The new generator will be able to generate enough electricity for a metropolitan area the size of Miami or Milwaukee -- 270,000 kilomatts -- Westinghouse said.

Rockwell International Corp. reported first-quarter earnings for fiscal 1979 of $64.7 million ($1.83 a share), an increase of 55 percent over fiscal 1978 first-quarter income of $41.7 million ($1.19). Sales totaled $1.5 billion, an increase of 15 percent over the previous year's first-quarter sales of $1.3 billion.

Rockwell President Robert Anderson said the earnings reflected improvements by the earnings reflected improvements by the company's automotive and electronics businesses.

Champion International Corp., a producer of paper and building materials, had record sales and earnings last year and improved results for the year's final quarter.

The company earned $168.68 million ($3.32 a share) for the year against $138.61 million ($2.13) in 1977. Sales rose 11 percent to $3.47 billion from $3.12 billion.

For the fourth quarter, Champion earned $25.63 million (46 cents) on sales of $875.73 million compared to $15.27 million (27 cents) on sales of $769.61 million for the final 1977 period.