EDIT: Also, "0.6% Of GDP growth" typically means 0.6% as relative to total GDP, not to whatever growth was expected to be. Yes it's stupid, but it's also the standard nomenclature.

And the direct quote from the article is "By one estimate, a production halt would shave about six-tenths of a percent off the gross domestic product growth rate, the financial equivalent of a prolonged government shutdown or a significant natural disaster", which clearly intends for 0.6% to be relative to GDP and not GDP growth.

That's not how economies work. The people who work at Boeing take home money and spend it in the local economy. That effect happens several times for each dollar taken home. Same thing happens for Boeing suppliers, they pay their people and those people spend in to the economy with a multiplier effect. This, spending money earned by workers, is how the engine of the economy is fueled when it is healthy.

Who do you think is going to be paid the dollars that Boeing workers are spending now, if they shut down?