CS people are not the main revenue driver for an aerospace company. Aircraft have been built without software engineers for over a hundred years, and they still are being made that way in some places. Software devs are still often seen as branch from the IT department. Most of the work is in supporting the actual aerospace/mechanical engineers, and is stuff like internal tool development, data engineering/warehousing. You're not doing any physical testing or generating drawings for parts, which constitute the actual IP worth billions that is used for manufacturing planes. For mechanical engineers the salaries are quite competitive and in line/better than other companies. These are generally much lower than FANG salaries for software engineers.

I've found the pay to be decent. The culture on the other hand is horrific.