This novel is perhaps based on
Operation Skyshield, a series of ADEXes held between 1960-62.
Skyshield I and
Skyshield II appear to have been particularly successful; however, the US Defence Department tried to downplay the Vulcans' successful penetration of the CONUS ADIZ and simulated destruction of major US city targets...
Which was hardly surprising, given the state of contemporary Cold War tension.....