Trans World Airlines, Inc., yesterday reported record net income after taxes of $53.4 million for the first nine months of this year, up 37.1 per cent from the same period in 1976.

TWA chairman Edwin Smart said 1977 may be the firm's most profitable year since 1965, when it earned $54.1 million.

For September alone, TWA said it had a report profit of $20 million, up 64.1 per cent from the same month last year.

That contributed to record third quarter earnings of $72.9 million, an increase at 33.5 per cent over the same time a year ago, the company said.

"Our strong profit performance so far this year reflects an outstanding performance from our Hilton International subsidiary as well as a solid contribution by our Canteen Corp. subsidiary," said Smart. "Also reflected in our results is a higher level reflected in our results is a higher level of international airlines traffic and the favorable impact of the 1976 Tax Reform Act."

Monsanto Co. third quarter net income plunged to $24.9 million (66 cents a share) from $63.4 million $1.69) a year before as sales rose to $1.076 billion from $998 million.

Chairman and president John W. Hanley said earning were lower than expected because the firm decided to write off fixed assets used in the manufacture of Cycle-Safe beverage containers. The Food and Drug Administration has prohibited the use of acrylonitrile in the manufacture of the plastic beverage containers.

American Can Co. reported record earnings and sales for the third quarter and first nine months.

Net income for the quarter ended Sept. 30 was $38.489 million ($1.96 a share), up 10 per cent from $34,937 million ($1.78) a year earlier. Sales rose 12 per cent, to $954.7 million from $852.48 million.

For the first nine months, net income was $88,055 million ($4.46) and sales totaled $2,647 billion. Comparable figures for 1976 were net income of $79,259 million ($4.02) and sales of $2,398 billion.

Celanese Corp., a diversified petrochemical concern, reported net earnings for the third quarter rose 71 per cent on a sales increase of 19 per cent.

For the first nine months, however, earnings dropped 9 per cent on an 8 per cent gain in sales.

In the third quarter, the company earned $21 million ($1.42 a share), up from $13 million (83 cents) in the same period last year. Sales totaled $591 million against $496 million.

For the first nine months, net income came to $55 million ($3.69), down from $60 million ($4.05) in the corresponding 1976 period. Sales rose to $1.7 billion from $1.6 billion.

A reduction in foreign exchange losses in the 1977 third quarter from 38 to 5 cents was largely responsible for the strong showing. Foreign exchange losses were trimmed to 18 cents in the first nine months of this year from 55 cents in the same 1976 period.

Cyanamid Corp., a chemical and pharmaceutical firm, announced a 9.2 per cent rise in third-quarter earning on a 21.3 per cent sales advance.

Third-quarter net income was $31.9 million (67 cents a share) compared with $29.2 million (61 cents) a year earlier. Sales climbed to $604.6 million from $498.3 million. Third-quarter sales included $47.7 million in revenues of Formica International, which became a 100-per-cent-owned subsidiary in April.

For the first nine months, the company earned $102.8 million ($2.15), down 1.4 per cent from $104.3 million ($2.18) in the same 1976 period. Sales, however, rose 13.7 per cent to $1.77 billion from $1.56 billion.

Lower first-quater earnings affected the nine-month results, more than offsetting gains in the second and third quarters.

Republic Steel Corp's third-quarter net income was off 47 per cent from the corresponding period last year, despite an increase in dollar value of sales.

Republic said the net income for the 1977 period was $10 million (62 cents a share) on sales of $751.2 million compared with $19.1 million ($1.18) on sales of $679 million for the third quarter of 1976.

W.J. Delancey, president and chief executive officer, said factors contributing to lower earnings included increased labor costs effective Aug. 1, "the adverse effects of strikes and work stoppages at iron ore and coal mining operations, a fire at the company's Warren, Ohio plant . . .and the sharp increase in foreign steel imports."

DeLancey said steel imports "were substantially higher than we had anticipated, accounting for nearly 20 per cent of steel consumption in the United States. Much of the imported tonnage in the quater came into Great Lakes ports and was directed to markets which we normally serve."