He will always be at the head of the stack of resume's compared to those who don't have one, all other things equal. When jobs are tight, having the degree will show the value.
Possibly. It entirely depends on the job being applied for. If I need a general staff accountant, I'm probably not looking for people with master's degrees for it, exclusively. Most people with graduate degrees and requisite experience are not going to settle for bachelor's degree compensation and title. Your statement will be entirely dependent on the specific job applied for. Also, my response included a question about his experience level. Experience trumps paper in almost every case, at least in my profession (accounting/financial analysis).
I haven't looked at all course catalogs for grad schools, but most don't offer a "generic MBA". You have a concentration/major etc. That is what sets up your depth of your classes. I am sure that there are some in "management", but you would have focused management classes. (There likely are "general business" options at some schools, again, more indepth than the undergrad.
Most of the programs I investigated have a "General MBA" program, and then they offer "specializations" or "focuses" if you want to look at a particular field (like energy, entrepreneurship, etc). If everyone gets a general MBA, then he's just one of the many. If he decides to go with a Masters in Finance, or Master's of Accountancy, or even MBA/JD, he's set himself apart from the crowd. YMMV
Him having or not having an MBA will not change your time allocated to "babysit". And, just as you would take the "BA/BS and 4 years of experience" you would likely also take the M"BA/BS and 4 years of experience".
I respectfully disagree. While there may be that diamond in the rough who is able to jump right into a mid-level job as a wet-behind-the-ears accountant, most of them have never used accounting software. They have never had to conduct business meetings or deliver financial results other than maybe in some group project in school. It takes a lot of time to teach/hone those skills, many times a few years. So the accountant with no Masters who has used Peachtree, or SAP, or CostPoint, MS Solomon, etc for a few years can jump in and with a chart of accounts and be productive with little instruction.
Again, there will always be exceptions to the rule. In my experience, I've had to work with a number of new CPAs who honestly make me lower the value of a CPA. I have worked with people having Masters degrees in other fields that I can't fathom how they graduated with a BA/BS, much less the Masters. I have worked with non-degreed employees who can work circles around CPAs because of their experience level.
So, my question for the OP, is what is his current experience level, and what is it he is wanting to do? No doubt that a Master's degree will likely pay off in the end, but is now the correct time to do so and is it necessary for his chosen career-path? If I were the OP and I had no idea what I wanted to do after I finished with the service and/or flying, I would probably wait and evaluate my needs once that point was closer to realization. No point in building an ark if you don't predict a flood, unless you just enjoy building arks.