It makes sense, I mean we are already in the forefront of technology like blockchain so what not take advantage of it. They know that blockchain can offer more secure way of protecting their data and it's easy to maintain.
Besides blockchain is adaptable and it's truly design to handle massive amounts of data, data that is the lifeblood of any organisations today including the military force. Not just airforce though, almost all huge companies now are moving to blockchain so I'm not surprised that US military is also moving forward this technology.