Lawyers for four men convicted of plotting to bomb synagogues in Riverdale and shoot down military planes at Stewart International Airport insisted yesterday the men were entrapped by the government.

In almost 2 1/2 hours of arguments, attorneys for the four men insisted before the U.S. Court of Appeals for the Second Circuit there would have been no crime but for the FBI and a perjuring confidential informant hatching the plot, providing the means and offering money to James Cromitie, David Williams, Onta Williams and Laguerre Payen.