Robert P. Nimmo, who resigned under fire last October as head of the Veterans Administration, liked to travel first class, often arrived several days early at attractive meeting sites and frequently arranged business trips that took him close to his home in California, according to a General Accounting Office report released yesterday.

The GAO said that Nimmo traveled first class, without the written justification required by federal travel regulations, on 14 of the 22 official business trips he took while in office. First-class travel for Nimmo and an assistant cost $8,600 more than tourist class. Nimmo also commandeered an Air Force plane in September at a cost of $5,602 to fly him from Reno to Washington for a luncheon, avoiding an overnight commercial flight, the report said.

The GAO said Nimmo frequently arrived several days early on business trips to resort areas, including a trip to Honolulu in which he arrived four days before an American Legion convention was to begin.

The GAO also reviewed other, previously reported practices of Nimmo, including his use of a government driver to chauffeur him between home and the office. Before resigning, Nimmo refunded $6,411 to the government for the chauffeur.

In his reply to the GAO, Nimmo said his failure to justify the first-class travel was a "technical error." He said that his refund was "an appropriate resolution of all the ambiguities presented."