In a sense he is correct, whatever uniform you wear makes no difference to how you do the job; would you really be any worse at your job if you woke up one morning and were told you were now in the army or navy?
However his argument falls right down when he suggests that
“The Air Force also has a history of letting costs get out of control,” he said. “When that happens, they have to cut how many things they can buy.”
USS Gerald R. Ford was estimated to cost $8Bn in 2008, in 2013 was estimated to be $12.8Bn, and it is now possible completion may be delayed 2 years beyond its initial 2016 plan. Can't imagine the cost will remain stable throughout.
The Marine-led Osprey program his been similarly affected by cost escalation, not to mention timescale.
No idea about tanks and choppers, but one supposes that as M1 Abrams is likely to remain in service for some time, either by being upgraded or replaced on a 1 for 1 basis, and likewise the AH-64E is also a development of an extant vehicle, then development and production costs are likely to remain better under control than new from the ground up designs.
Whilst it's true that many USAF programs have got ever more extensive and delayed, they, for the main, been intended at least to represent huge capability leaps over their predecessors. I would also suppose that F-35 would been significantly cheaper had it not been hobbled by a requirement for STOVL.