I worked in aerospace for 19 years after leaving the USAF. It all went away in an unbelievably short period with the "peace dividend" group think. The handwriting was on the wall long before the jobs went though.
The people I know that made it adapted and overcame. They went from making cruise missile to GPS trackers and doing bio-medical research. They moved to where the jobs are. In many cases that was half way across the country.
Some went through entire career vocational changes, they took the risk to go back and get educated for new skills rather than wait for someone to tell them what to do.
No many in middle age can adapt so easily. As Trump says again and again, the theft by China from US wealth is the biggest theft of all time. He is right, we built China.