SkyHigh is correct in one sense: most military officers have a variety of mechanisms by which they can earn a masters, either partly or fully funded by the government, and in some cases they have no other duties but full-time post-graduate school. This is necessary and entirely justifiable from the perspective of ensuring that we have officers who can participate in and oversee advanced-technology R&D programs, as well as ensuring a supply of well-rounded senior officers.

With that being said, I think there are a lot of airline pilots with masters degrees who got hired at a major because of their military flying background, not because of their advanced education.

I'm sure a master's would never hurt, and will likely help a little at some companies. If you have the time and money, go for it...but get one in something non-aviation in case you ever need to fall back on it.

Also, I wouldn't waste money on random type-ratings for airplanes that you don't fly (well maybe a 73).