Just FYI: P-8 doesn’t have A/A radar. “The P-8A Poseidon is an aircraft designed for long-range anti-submarine warfare; anti-surface warfare; and intelligence, surveillance and reconnaissance missions”
http://www.boeing.com/defense/maritime-surveillance/p-8-poseidon/
Without A/A radar, how are they kept aware of airborne threats? Do they link up with an AWACS?