Is the air fed to the cabin of passenger jet filtered, and recycled, does the captain breath separate supply?

Why is it every time I fly, I catch the Flu ?
I can only assume I am breathing the same contaminated air as the rest of the passengers, one with a flu sneezes, we all have it !
How do the flight crew manage, do they get flu shots?
Also the captain in my mind, should be on a separate supply, due to terrorisim possibilities with a nerve gas etc?

The air is filtered on the airplane. One of the worst jobs you can have in aviation it to have to Clean the filters. You can't believe how bad they are. Air quality is notorious on the airlines. You can help yourself stay healthy by using several different products. the one I remember right now is called "Airborn" you take it before you get on the airplane and it boosts your system. All air intakes are guarded on air-flights and the pilots and front cabin crew have access to alternate emergency oxygen supplies.

My first year as a flight attendant, I got sick a few times. My immune system must have just gotten used to it. I also take airborne while I'm flying, and drink A LOT of water to stay hydrated. The air in the cabin is recycled, but the air quality in the plane is not great. The pilots do have oxygen masks, that they can use if they want to. I see some use them all the time, and some just take a few breaths through it every now and then.