It's the Air Force that is saying they will have to cut 40,000 to meet "constraints"...in other words, they're putting some major additional spending priorities into their budgets that bust the bank and they have to come up with an in-house way to pay for it. It's also a form of coercion that works sometimes (this is nothing new); they make unpopular threats in the hopes that Congress will relent and chock up additional funds to pay for their new toy. A good example is the way the Coast Guard used to deal with anticipated budget "constraints". They would announce that in order to meet these "constraints" they were going to have to close down Air Station Chicago (two whole rescue choppers but to a budget the size of the Coast Guard's it added up) and a few other high profile units...always in the districts of Congressmen with clout and vocal constituents. Those constraints come in the budget guidance that comes down to the services from DoD. It's not at all the same sort of thing as threatening to close Representative Foghorn's pet facility. These cuts will be scattered through out the force. Old Foghorn won't much care because the pain will be spread out so much, he'll likely not notice, unless one of the programs that gets the axe was in his district
DoD doesn't dictate how each service allocates it's money, it provides the budget and oversight only.
People are making way too much out of this story.