Can heated air be provided in the cabin in commercial airlines? Having travelled quite a number of times, there are times, when the cabin becomes a bit too cold, or people with certain condition get shivering quickly. In such circumstances and generally, is it possible to request for heated air in the cabin. If not the entire cabin, but atleast to specified seats, via the air flow controller on top of the head.

Before that, are airlines equipped to provide heated air, like in a car?
The fresh air vents near your head at each seat can not be adjusted for temperature individually.  Cabin temperature is controlled. Just ask a Flight Attendant to warm it up as they have a control panel to adjust cabin temperature by zone. 

Most modern airliners use bleed air from the engines to power two Air Conditioning Packs which circulate cooled or heated air throughout the cabin. 

Environmental control system (aircraft)

B777 Air Systems