Andy, you are viewing a different unit. As you should be aware, interceptors and helicopters are not the same as bombers and fighters.
Go to "Setup Air Wings". Click on your "Defense Interceptor Wing" link there, to view the stats of that type of unit. In the window that pops up to display there, it shows 480 interceptors comprise such a unit. Now, try to ACTUALLY make a unit with 480 interceptors.
It seems logical after viewing that window that you should purchase precisely that number of interceptors to form a proper interceptor unit. The problem is that you can't. Next, try this with a "Defense Helicopter Wing", or try to form a "Airforce Stealth Bomber Wing" which similarly says such a unit compromises 130 stealth bombers.
The problem Andy is these links should provide especially newer players the information they require to purchases the proper number of weapons to form units, but, instead, provide a number that is above what they can actually create a unit with. These are the specific unit types I have detected this discrepancy with but I suspect there could be more.