Falcon 4 Allied Force works differently than Falcon 4 BMS 4. You must first choose a theater where increasing the number of barcaps is even possible. The instructions will be broken down by theater.
Increasing the number of barcaps of the Korean theater is possible on the Allied Side. However, increasing the number of barcaps on the enemy side is not. The number of barcaps on the enemy side is so few that is not even really playable. Literally only about three or four barcaps for the entire enemy side will be present at one time once the campaign gets going. Unfortunately, if you want to have any air to air resistance when striking airbases, you will need to choose another theater. Korea, Korea 2005, and Korea 2010 all have the problem of not generating enough barcaps.
The Balkans theater works pretty well at generating enough barcaps. Try fast forwarding the game 64 times. Check whether there is a whole screen worth of defensive counter air missions well into to the campaign- like four or five hours into it. If the number of barcaps dwindles a lot, then you might want to adjust the priorities to make the game harder.
The game can be made a lot harder by adjusting the priorities to generate more barcaps. In fact in Balkans 2010, the priorities can be adjusted in such a way that it makes NATO get soundly defeated and greatly need your intervention. The only limitation is that you may have to choose between heavy air to air resistance and no enemy air interdiction of vehicles missions or enemy airbases strikes.
1. Make it so that you can fly any plane. In the Falcon 4 Allied Force folder, go to the campaign folder. Then go to the folder that has the name of the theater you wish to play. For example, if you wish to play the Balkans 2010 theater, go to the Balkans 2010 folder. In that folder there would be a file named validAC.bin. Change the name of this file. A good name to change this to is xvalidAC.bin. If you name it that name, then the file will be easy to find. This will make it so you can change it back to validAC.bin if you want the aircraft you can fly to be restricted again.