Trust me, they don't secure the press plane at all. All you have to have is an Airline uniform and you have full access.
Now Air Force 1, or 2..... Even the Porta-potty truck is escorted, and nobody is allowed up the stairs without a "Blue Badge" and escorted by the Loadmaster.
I used to coordinate Diplomatic Clearances in Delhi and in Argentina. I handled Bush's visit to India in 06.