Sununu’s Stature Suffers After String of Difficulties : White House: Administration officials say powerful chief of staff is no longer unchallenged. Problems are traced to budget talks last fall.

WASHINGTON — Nearly six weeks after controversy began over his frequent flying on government aircraft, White House Chief of Staff John H. Sununu remains a powerful--but no longer unchallenged--figure within the Bush inner circle, according to numerous Administration officials interviewed in recent days.

Where once even high-ranking officials quailed at the mention of Sununu’s name, now even lower-ranking aides are demonstrating a willingness to criticize the irascible chief of staff, reporting on incidents in which his temper or his personal idiosyncrasies have created problems for Bush initiatives.

There is no sign that President Bush is prepared to remove Sununu from his post. But there are signs that Sununu has lost some of his power.

Most recently, a lawyer on the staff of White House chief counsel C. Boyden Gray publicly challenged Sununu’s delay in reimbursing the government for some of his airplane rides. Sununu’s office says that the delay was a result of a billing error, but the willingness of a lower-level staff aide to criticize him on the record indicates a marked change of tone at the White House.

Sununu’s problems are most often associated in the public mind with the airplane controversy, which began when the Washington Post and U.S. News & World Report disclosed that the chief of staff had taken scores of flights at taxpayer expense on government planes, including several trips to ski resorts and political events and on personal errands.

A report on the flights by Gray criticized Sununu’s practices, although it exonerated him of charges of having broken federal ethics laws. Bush has ordered new policies designed to restrict the sort of travel that sparked the controversy.

But, although the travel problems have attracted the most public attention, White House officials trace Sununu’s difficulties to an earlier set of events--the disastrous negotiations last fall over a federal budget package. As the chief Administration negotiator, Sununu alienated many key members of Congress. More important, the process ended up putting Bush in a series of embarrassing positions that caused a sharp, although temporary, drop in the President’s poll ratings.

Bush publicly stood by Sununu during and after the ordeal. Privately, however, “the President’s unhappiness with the staff work was made clear,” an Administration official said.

Since then, Sununu has lost some major battles within the Administration. In one example, the chief of staff publicly denigrated a major banking reform proposal that has been pushed by Treasury Secretary Nicholas F. Brady. After complaints by Brady, Bush publicly endorsed the proposal and has subsequently done so several times.

The latest controversy involves Sununu’s payments for his airplane rides. Under government rules, Sununu is required to reimburse the Air Force for any “non-official” travel he takes on a military plane. The reimbursements are done at a rate equivalent to a commercial coach ticket, although the military planes cost far more than that to operate.

In several cases, however, Sununu waited for months before making the reimbursements. Friday’s Washington Post quoted Gregory S. Walden, an attorney on Gray’s staff, as saying that Sununu had been unable to “identify to my satisfaction” a reason why the payments, a total of $3,768, had been delayed. Sununu paid the money out of leftover campaign funds.

A Sununu aide said the problem was that the bills had not been delivered to Sununu’s office. However, others who rode on the planes in question did receive their bills and paid on time.