After months of holding their peace, some members of the Fairfax County Board of Supervisors have begun to expreses open criticism of Chairman John F. Herrity's aggressive style of leadership.

"They all like Jace. He's a good, decent guy," said Vice Chairman Martha V. Pennino (D-Centreville) of her colleagues on the nine-member Board. "But he's developing a high political profile, and that seems to be resented."

Although he chairs meetings and occupies a comfortable 11th-floor suite in the Massey governmental center in Fairfax City, Republican Herrity is supposed to reflect the collective policy of the Board. The other supervisors are supposed to be consulted on all decisions, even seemingly minor oes about vacation schedules.

But it hasn't worked out that way, some of the supervisors complain.

On Dec. 13, the supervisors discovered they wouldn't be meeting again until Jan. 10. The four-week vacation had been scheduled by Herrity and the county staff.

There was no public criticism of Herrity at the time, but Supervisor Marie B. Travesky (R-Springfield) remarked obliquely that the several-inches-thick agenda for the Dec. 13 meeting was too much material on which to make judgment in a one-day sitting. Supervisor Audrey Moore (D-Annandale) expressed her annoyance about the extended vacation to Herrity in private.

But now Mrs. Moore and Mrs. Travesky cite the vacation scheduling as just one example of Herrity's tendency to got it alone.

On Monday a number of the supervisors criticized Herrity of writing a year-end review article for the Virginia Post in which, according to Mrs. pennino, "he did everything and the Board did nothing." The article appeared Dec. 30 in the middle of the supervisors vacation.

Herrity pointed ot that he had been asked by the editors of the Weekly to prepare the article.

What Worries the supervisors, according to Mrs. Pennino, is that Herrity "is doing things that commit the Board to policy-type decisions . . . Jack says no one has discussed this with him, but it's not true."

Herrity himself sys, "I'm not perfect. I'll make some adjustments where necessary."

He said he plans to hold individual meetings with the other supervisors over the next few weeks. "I'm going to reconnoiter a bit," he said, conceding he can "be a little aggressive, and I speak my mind."

While there have been expected an open clashes between Herrity and some supervisors on controversial issues, the chairman, according to one supervisor who would not be named, has been criticized in executive session for "grandstanding" on Metro.

Supervisor John P. Shacochis (R-Dranesville) acknowleged he has criticiced Herrity for suggesting he was speaking for the Board while attacking Metro finances and projections." We've straightened him out on that," Shacochis said.

On the other hand, the Dranesville Republican said that now, "I personally do not have any complains," even about the Herrity authored article, which he said he liked.

While criticism is only now coming to the surface, Mrs. Pennino said "this time." She and other supervisors said attempts were made to deal with the problems privately. But, they said, those effrs seem to have failed.

In the first half-year of his chairmanship, which began a year ago, Herrity assumed undisputed leadership - seizing and holding the initiative during a budget crisis, and getting the supervisors to reverse key decisions made by the previous Board, headed by Jean R. Packard, the Democrat Herrity defeated in 1975.

Herrity has been able to win majorities on several key Board votes involving Metro. But on Monday he was defeated 7 to 1 when the Board decided, after all, to pay its share of the first-year Metrorail operating budget (covering the initial subway route between Farragut Square and Rhode Island Avenue).