Fairchild Industries Inc., an aerospace and communications company based in Germantown, yesterday reported substantial increases in sales and profits for the fourth quarter and all of 1977.

And Peoples Drug Stores Inc. reported a sharp rise in earnings for the first quarter of its new fiscal year.

Braced with a backlog of commercial and government orders that exceeded $1 billion at the end of 1977, Fairchild recorded fourth-quarter earnings of $3.5 million (76 cents a share), more than doubled the $1.6 million (35 cents) posted a year earlier. Sales rose to $112 million from $84 million.

Earnings for the full year soared to $9.6 million ($2.05) from $4.9 million ($1.07) in 1976. Sales were a record $399 million compared with $264 million the prior year.

Behind the sharp advances at Fairchild were increased deliveries of commercial and military aircraft. During the year, Fairchild delivered 56 new A-10 close support fighters to the Air Force and received a formal Pentagon contract for an additional 144 of the planes.

Fairchild is turning out six A-10s each month and, on Dec. 31, had firm contracts for 263 undelivered planes with a contract value of $878 million.

The company's commercial aircraft subsidiary, Swearingen, also set sales and profits records last year. Swearingen delivered 38 executive and commuter planes last year and had a Dec. 31 backlog of orders for 35 aircraft, a record.

Peoples Drug Stores of Alexandria reported a 17 percent increase in profits for the quarter ended Jan. 14. Earnings rose to $2.4 million (67 cents a share) from $2.1 million (56 cents) in the comparable period a year ago. Sales were up a modest 7 percent to $130 million.

Company officers attributed the earnings increase to improved merchandising techniques and better operating efficiency, but they cautioned Christmas selling season, traditionally the most profitable.

Five new stores were opened in the 16-week quarter and 12 more units are planned over the balance of the fiscal year. One of the nation's largest retail drug chains, Peoples operates 380 stores from Georgia to the Midwest.

Survival Technology Inc., a Bethesda developer and manufacturer of emergency medical care products, reported a sharp increase in profits for the second quarterended Jan. 31. Earnings totaled $377,484 (15 cents a share) compared with $23,062 (1 cent) a year earlier. Sales rose to $2.78 million from $1.89 million.

The profitable quarter brought Sur-Tech's six-month earnings to $24,516 (1 cent) compared with a loss of $195,923, as sales rose to $3.7 million from $2.7 million. Officers said that current sales and production activity indicate "continued profitable operations throughout the fiscal year."

United Nuclear Corp. of Falls Church reported record profits in the third quarter ended Dec. 31 of $7.3 million ($1.15 a share) compared with $5.5 million (87 cents) a year earlier. Revenues rose 51 percent to $64 million.

For the first nine months, the company earned $20.8 million ($3.27) vs. $15 million ($2.37) as sales increased 49 percent to $175 million. Improved results were attributed to increased uranium production and higher selling prices.