What really happens when those big automative / aerospace companies close down?

Massive automotive companies often take on a huge amount of employees on their spralling plants / sites, which inevitably leads to an equally huge wave of unemployment when such a company hits hard times and has to shut it's doors for the last time.

A shame you would think for those workers but, in time they will mostly be able to find new work again elsewhere for the most part? In reality it takes a lot of time for so many workers to find new jobs in such a localized area. Especially since most are qualified to do exactly the same kind of work, competition is rife etc.

That's just the tip of the iceberg however. All the other smaller engineering firms that base their vast majority of their income on contracts to the automotive company in question (be it for components mainly) up & down the country slowly start to head the same way, especially those that put all their eggs in one basket so to speak. Such is the importance of such firms to other smaller engineering firms. It's just like cutting off their food supply.

Again these smaller firms leave behind more mass unemployment over the next months / years.

As such you could say why such companies could be of high importance to an economy. However with production costs so low elsewhere in the world, perhaps it would prove an even harder task keeping those companies that are still going strong, where they are?