FACTBOX - How strike affects Boeing

(Reuters) - Boeing Co's 27,000-strong machinists union is on strike, halting commercial airplane production, after last-ditch talks failed to agree to a new labour contract by a deadline of midnight Seattle time on Saturday.

Boeing says plants will stay open, with workers in other unions and non-union employees expected to report, but production lines at its massive facilities in Everett and Renton, Washington, will halt assembly.

If the fourth Boeing strike in 20 years is prolonged, here are some of the financial losses and problems predicted for the company and an increasingly worldwide supply chain. Economists also anticipate a drag on the Seattle-area and U.S. economies.

BOEING

-- Boeing could lose up to $3 billion (1.7 billion pounds) in revenue per month, half the company's expected monthly total, if deliveries of its commercial planes are halted, based on figures from the first half of the year.

-- It could lose 30 cents to 40 cents from earnings per share for each month of a strike, according to Wall Street analysts. The company is expected to earn $5.85 per share for the year, on average.

AIRLINES

-- Delivery delays would inconvenience major airline customers such as AMR Corp's American Airlines, Continental Airlines and Southwest Airlines Co.

-- Buyers of the new 787 Dreamliner, already angered by production delays, would face an even longer wait. Big customers include Japan's All Nippon Airways, Australia's Qantas Airways, Britain's Virgin Atlantic and Singapore Airlines.

-- U.S. plane leasing company, International Lease Finance Corp, a unit of insurer American International Group Inc, is the biggest 787 customer, with 74 on order.

-- A lengthy work stoppage could be an opportunity for rival Airbus, a unit of EADS, to pick up some plane orders from uncertain airlines.

SUPPLIERS

-- If Boeing's plane production lines stop, suppliers will stop or reschedule deliveries, causing inventory pile-ups and possible layoffs. Boeing's major suppliers include:

-- General Electric (engines)

GE supplies its own engines for some wide-body models and its CFM International 50-50 joint-venture with France's Safran supplies all the engines on the 737 single-aisle series, Boeing's top-selling model of aircraft.

-- Pratt & Whitney, a unit of United Technologies Corp (engines)