Navy P-3 AIP (Anti Surface Warfare Improvement Program) reconnaissance aircraft proved useful to marine ground units in Iraq, but only if the marines put a senior marine officer (usually a colonel) on the P-3s. This insured that the P-3 crew was constantly reminded of what the marines on the ground needed, and the P-3 was not "hijacked" by some other headquarters for a recon mission that was of no use to the marines. 

The AIP version of the P-3 has synthetic-aperture radar and electro-optical cameras that provide real time video, day and night, of surface areas. While this capability is useful at sea, the marines have discovered that the P-3 AIP is an excellent recon aircraft to support their ground operations. The P-3s carry enough countermeasures to protect them from portable anti-aircraft missiles, and can stay in the air over a marine unit for ten hours or more at a time. The P-3 has a satellite link and GPS onboard. The land recon versions of the P-3 can carry and use Maverick guided missiles and Harpoon missiles (configured for hitting ground targets). The aircraft also has equipment to detect and identify enemy radars operating in the area. 

But such a capable recon aircraft is in great demand, so the marines learned that if they could get a colonel on board the P-3, they would basically "own" the P-3 for that flight.