Low hot water pressure, air in the lines

I live in a mobile home with well and septic. My hot water pressure has been getting lower lately, cold water pressure is fine. A freind recommended I drain the water heater to improve the water pressure. After I did this my wife turned on the washer and the water is coming out slow and is rust colored. Also when I turned on the other faucets in the mobile home the water comes out in spurts and it is obvious there is alot of air in the lines. By the way the hot water pressure never improved. What can I do to clear the air out of the lines.

Hopefully, when you drained the hot water tank, you turned it off first, otherwise, especially if it was electric, you may have ruined the heating elements. If galvanized nipples were used at the top of the hot water heater for the connection, then that could be your problem - they could easily be filled with rust, restricting the flow. The other very possible problem is that the aereators or screens on the input to the faucet or showerhead are clogged with debris.