Thats not correct English so I shall explain better.
The object dropped that you are speaking of is a counter measure to a heat seeking rocket called a flare. These heat seeking rockets will only attack you if you fly over area 69 (the no fly zome on your map.) Launch a flare and the rocket will follow the heat from that rather than your Hydra. The rockets are lauched via SAM (Surface to Air Missile) sites posted near Area 69. Heat seeking rockets appear and tiny red triangles on your Spin Map, if you see one lauch some Flares and you shall keep your self out of serious trouble.