The Histadrut labor federation, the umbrella organization for hundreds of thousands of public sector workers, said the strike - which the Treasury estimates is costing the economy $500 million a day - would also halt trains and close the Bank of Israel and government offices. Ben Gurion International Airport near Tel Aviv was shut for an hour and a half. An airport spokesman said regular activity had resumed but a new flight schedule was still being drawn up. Histadrut wants the government to hire about 250,000 contract workers, such as cleaners and security guards, whose working conditions are inferior to workers directly on government payrolls. The Finance Ministry said it cannot take on that many new workers but has offered to improve their conditions by raising salaries by at least 20 percent and giving them more holidays.