General Dynamics Corp. has withdrawn its request that the Pentagon pay $491,840 for 76 trips by the defense contractor's chairman in the corporate jet from St. Louis to his farm in Albany, Ga., government and company officials said yesterday.

Chairman David Lewis' trips were among items challenged by the Pentagon's Defense Contract Audit Agency in questioning $22 million in corporate airplane travel billed to the government between 1978 and 1983.

Navy Secretary John F. Lehman Jr. yesterday told a joint meeting of two subcommittees of the House Armed Services Committee that the Navy's relations with General Dynamics improved markedly since P. Takis Veliotis left as manager of its Electric Boat Division in November 1981.

"There is no cause for believing there is anything wrong with the way the Navy does business with General Dynamics," Lehman testified. In 1981, he said, General Dynamics sought but did not receive Navy help in obtaining "ridiculous" claims for insurance money to reimburse Electric Boat for losses stemming from shoddy work on Los Angeles-class attack submarines.

In a separate development, Lewis; Gorden MacDonald, the company's chief financial officer, and Edward (Ted) LeFevre, vice president for government relations and head of the Washington office, appeared Tuesday before a federal grand jury in New Haven, Conn., investigating allegations of fraud by the company on submarine-building contracts.