For what it’s worth, here is my take.
If you aspire to management then a MBA is the way to go. If you want to be a cubicle warrior in flight ops then your masters in aviation will do just fine. Managers just want people who will do the grunt work of updating manuals, dealing with ops changes and interfacing with the federales.
If you are established in the career as a line pilot then get a degree in something that interests you. I have several friends that got law degrees after being caught up in the legal battles we had during our previous merger. They are actually doing quite well with their practice.
Other pilots I know have become home contractors, high end motorcycle constructors, real estate agents, just about anything you can think of. The key is, they were established on a seniority list they were not going to move from. Once you have the time and the schedule you can spend a fair amount of time pursuing a degree.
I got an BBA in business years ago and worked as a systems analyst when I was first building time. I wanted a degree that wasn’t aviation related as a fall back. That did pay off after the first few nonscheduled cargo operators I flew for cratered. But after a couple of years I was able to get on with a commuter and had to make a choice, cubicle dweller crunching code or flying. Flying won out and after a few years of starvation wages I was settled. And in those few years I quickly was outpaced in the tech world by new programs and languages. Back up plans and degrees work only as long as you can stay current in them!