If Wikipedia's list of General Motors factories is correct, the impact of a General Motors automobile workers' strike will be highly localized (the UAW, as I understand it, represents only workers in the United States, not those in Canada, Mexico, or other foreign countries). By state, General Motors has plants as follows:
New York 3
Kansas 2 (both in Fairfax)
There is one GM plant each in Delaware, Georgia, Kentucky, Louisiana, Tennessee, Texas, Virginia and Wisconsin.
General Motors has 48 plants abroad, including 9 in Canada (8 in Ontario and 1 in Quebec) and 3 in Mexico.