Not fired, that would indicate termination for cause. This was an early buyout. Engineers at those levels were offered a severance package that included some number of weeks of pay per years spent with the company (up to a maximum of 6 months of pay) and a base amount on top of that.

This was the precursor to layoffs -- LM hoped to avoid layoffs by offering buyouts to these engineers. The wisdom of all of this... I don't see it.

Their goal was to reduce total amount spent on salaries.

This came at the time that the F-35 flight test program began its long wind-down. Other companies were hiring in large numbers because they had just begun big test programs (NGC had just won the B-21 contract and was testing its Triton UAVs), the net effect was that a HUGE amount of engineering knowledge and talent went out the door within a year. I can only speak for what it did to the F-35 test forces -- basically made them start over in terms of learning how to execute their jobs.