Boeing Co’s commercial jet workers voted on Thursday to ratify a new labour contract that ended a four-week strike, kept intact most benefits and reopened factories for jetliner production.Eighty per cent of unionised workers at Boeing factories in Seattle, Oregon and Kansas voted in favour of the new contract. Some workers said they would return to shifts beginning as early as Thursday night.The three-year contract increased pensions and preserved health care and other benefits which the company had sought to reduce.Union leaders, who recommended that members vote for the contract, said it was a major victory for about 18,400 Boeing machinists.‘‘We want to build airplanes and we to build them under good conditions,’’ Mark Blondin, President of Machinists Union District 751 said.The end of the strike came as Boeing is experiencing healthy demand for its jet planes. Orders at the Chicago-based company are likely to overtake European rival Airbus SAS in 2005 for the first time since 2001, although Airbus retains a lead in plane deliveries.‘‘Our focus now shifts to ensuring a smooth restart of our production system and a return to a steady flow of airplane deliveries to our customers,’’ Alan Mulally, CEO of Boeing’s commercial airline unit, said in a statement.‘‘We have tremendous momentum in the market and a very bright future,’’ Mulally said.The strike was the shortest-ever by the machinists, reflecting in part healthy economic conditions for the company, a fact that union leaders recognised.‘‘With orders coming in, you feel you’ve got a lot of leverage,’’ Blondin said.Some analysts had expressed concern that Boeing would be forced to shut down production for months. When a deal was announced earlier this week, they said they were surprised by the quick resolution, after reports the two sides were far apart on issues like pensions, health care and job security.Union-friendly former Democratic Representative Richard Gephardt of Missouri helped Boeing in the talks and Boeing’s Mulally participated at the bargaining table. — Reuters