After three years of losses, Quality Inns International earned profits of $1.49 million in fiscal 1978, the Silver Spring-based lodging chain reported yesterday.

In other earnings statements, Hotel Investors posted an 18 percent gain for its latest fiscal year while Allegheny Airlines reported a 56 percent increase during the third quarter. Area banking companies listed third-quarter increases in profits that ranged from 11 percent to 69 percent.

Quality Inns lost $1.13 million in fiscal 1977 after losses of $1.4 million in 1976 and $2.7 million in 1975. The last year the chain turned a profit was in fiscal 1974, when Quality earned just over $1 million.

The profits in the recent years ended Aug. 31 amounted to 56 cents per share. Thus, the chain's profit represents a turnaround of nearly $1 a share from 1977's 43 cents per share loss.

Quality's total revenues for the year increased to $56.9 million last year, from $52.2 million the prior year. Before income taxes, adjustments for sale of property and foreign currency translations, the company reported operating results, of $2.6 million, in contrast with a $425,000 loss in the prior year.

The recent year was the best in Quality Inns' 39-year history, said company president Joseph W. McCarthy. He said the sale of five hotels, which produced a $2.1 million gain, had a significant impact on earnings but that revenues would have been "considerably higher" had the properties not been sold.

McCarthy said Quality Inns' improving financial status was indicated by its success in refinancing company-owned inns in Arlington, Va., and Catonsville and Towson, Md., and by its agreement to open 40 hotels in Mexico in partnership with Banco Nacional de Mexico.

The first of the mexican inns, a 220-room hotel at Puerto Vallarta will open in February and within the next year the chain hopes to add units in Cancum, Tampico, Merida,and Tijuana.

Hotel Investors, a Chevy Chase real estate investment trust, reported an 18 percent increase in earnings during the year ended Aug. 31 to $2.18 million ($1.40 per share) from $1.85 million ($1.20).

The REIT reported its gross income increased to $9.4 million from $9.2 million from its properties include hotels operated by Marriott, Hilton, Sheraton, Holiday Inn, Ramada Inn and Travel Lodge.

For the fourth quarter of 1978, Hotel Investors reported earnings of $461,000 (29 cents per share) up from $426,000 (28 cents) as revenues increased to $2.4 million from $2.3 million. A cash payout of 45 cents a share will be paid Nov. 2 to owners of record Oct. 18.

Allegheny Airlines reported third quarter earnings of $9 million (73 cents a share), up 56 percent from $5.8 million (60 cents) in the same period last year. That brought nine-month profits to $22.2 million ($2.05) compared with $9.3 million ($1.04).

"Results for the month, quarter and year-to-date continue to reflect substantial increases in passenger boardings . . . passenger traffic continues strong in October and we anticipate the balance of the year will continue on a very positive basis," said Chairman Edwin Colodny.

Third-quarter revenues were $153 million compared with $131 million while nine-month revenues rose to $420 million from $358 million. Revenue passengers totaled 9.6 million in the recent three quarters compared with 8.7 million a year earlier, partially reflecting discount fare programs.

Results for 1978 included a gain of $10 million from selling equipment compared with $334,000 in the same period last year.

At area banking companies, third-quarter profits were unusually strong. Joining such firms as Virginia National Bankshares and Riggs National Bank, which earlier posted sharp gains, Suburban Bankcorporation of Hyattsville announced yesterday 24 percent increase during the July-September period.

Not counting securities gains or losses, earnings were $3.59 million (80 cents a share) compared with $2.9 million (65 cents) a year earlier. Nine-month operatings profits were up 21 percent to $9.8 million ($2.19) from $8.1 million ($1.81).

Chairman Robert Tardio, whose assessment of strong profit gains echoed comments by other banking officials yesterday, said higher interest income from substantial increases in consumer and real estate loan volume was a major factor. In the case of Suburban, parent firm of Suburban Trust Co., average loans in the recent nine months rose 21 percent to $685 million.

United Virginia Bankshares Inc., of Richmond, that state's largest banking firm, reported an increase of 38 percent in third-quarter operating profits to $6.7 million ($1.24 a share) from $4.8 million (90 cents). Nine-month earnings were $18.8 million ($3.48 vs. $11.9 million ($2.21), a gain of 58 percent. Assets rose 9 percent to $3 billion and loan volume increased 18 percent to $1.68 billion.

First Virginia Banks Inc., a Falls Church bank holding company, reported a 14 percent increase in profits for the third quarter to $3 million (28 cents) from $2.6 million (25 cents). Nine-month profits were a record $8.6 million (81 cents) vs. $7.15 million (68 cents), an increase of 20 percent. Loan volume rose 12 percent to $805 million as assets increased 10 percent to $1.35 billion.

First & Merchants Corp., a Richmond holding company for banking operations throughout the state, reported third-quarter operating profits of $3.3 million (99 cents) vs. $2.5 million (77 cents), a 29 percent increase. Nine-month earnings were up 17 percent to $8.3 million ($2.54) compared with $7.1 million ($2.17). Loan volume was up 10 percent to $1 billion.

Dominion Bankshares Corp., of Roanoke, reported third-quarter operating profits of $4.3 million (69 cents) vs. $3.9 millkon (61 cents), a gain of 11 percent. Nine-month profits were a record $12 million ($1.92) vs. $10 million ($1.58). Assets were up 8 percent to $1.8 billion and loan volume increased 15.5 percent to $1.1 billion.

American Bank of Maryland, controlled by Financial General Bankshares, reported third-quarter profits rose 58 percent to 63 cents a share from 40 cents. Nine-month earnings were equal to $1.68 a share compared with 85 cents in the 1977 period. Loans volume rose 34 percent.

District of Columbia National Bank reported nine-month earnings of $494,707 compared with $342,960 a year earlier, an increase of 44 percent.Third-quarter earnings were up 69 percent and loan volume jumped 43 percent to $45 million.

Ryland Group Inc., a homebuilding firm based in Columbia, reported third-quarter profits dipped to $1.6 million (49 cents) from $2 million (60 cents) in the 1977 period. Nine-month profits declined to $4 million ($1.22) from $5.1 million ($1.53). Sales contracts signed in the recent quarter totaled $44 million, down 31 percent from a year ago but contracts outstanding on Sept. 30, $114.5 million, were up 4 percent.