Please explain 'incandescent air'.
Do i have to bring the dictionary as jroa does? Incandescent, i.e. very hot air, so that its EM emission in the visible spectrum is clearly visible. http://en.wikipedia.org/wiki/Incandescence
EDIT: With air i actually mean also the gaseous product of the reaction.
Here comes a nit pick, just because I do not want jroa to capitalize on a simple misconception to give credence to his useless idea.
The flame is not, in general, incandescent air. It is a mixture of air and a gas which is burning. You can heat enough the nitrogen and oxygen in the air so that they will become plasma and emit heat, but this does not happen in everyday household situations.
This is the reason why some very hot objects do not produce a flame but other, less hot objects do. Some components of wood vaporize and ignite while on top of the wood, producing the yellow flame. On the other hand, some metals burn producing characteristic colored flames which do not correspond to the color of the black body radiation corresponding to its temperature.
Lots and lots of questions are answered by our current knowledge of Physics and Chemistry, including the presence or absence of flame, the change in mass of a burnt object, the color of the flame, the amount of heat a chemical reaction produces, and so much more. On the other hand, phlogiston only explains the two or three things that medieval scientists already knew.