First American Bank of Maryland yesterday announced net income of $1.8 million ($1.25 a share) for the quarter that ended June 30, an increase of 38 percent over the $1.3 million ($1.04) for same quarter the previous year.

For the first six months of this year, net income totaled $3.4 million ($2.41) a 33 percent increase from $2.6 million ($2.08) for the first half of 1986.

Bank officials attributed the growth to a 24 percent increase in net interest income as a result of growth in loans and deposits.

The company also said it benefited from a widening spread between the bank's cost of funds and the rate earned on loans and investments.

Total assets increased $65 million from March 31, and on June 30 totaled $946 million, an increase of 20 percent from the previous year. Total loans increased 27 percent to $639 million and deposits increased 20 percent to $825 million from the prior year.

First American Bank of Maryland operates 36 offices in the Washington Baltimore corridor.

It is a member of First American Bankshares Inc., a bank holding company with total resources exceeding $7.2 billion.

Dyncorp, a technological services company with headquarters in McLean, announced net earnings of $1.9 million (18 cents a share) for the second quarter ending July 2, a drop of 21.8 percent from $2.5 million (24 cents) for the same period in 1986.

Revenue for the second quarter was $213.8 million, a 15 percent increase from $186.3 million for the same period the previous year.

The drop in earnings resulted from costs related to an antitrust conviction and related litigation involving a subsidiary. The company said, however, that payment of the fines has been stayed by the court until resolution of the appeal.

Net earnings for the first half of 1987 were $1.3 million (12 cents), a drop of 62 percent from $3.5 million (35 cents) for the first half of 1986.

Revenue was $413.4 million, an increase of 18.7 percent over $348.2 million during the first six months of 1986.