Actually, as I understand it, the term was indeed coined in the 20th century in response to the German invasion of Poland. It was a journalists tool to sell papers describing a 'frightening new form' of warfare, which, of course, people had to buy the newspapers to learn about…
But while I agree with everyone who says that maneuver warfare was practiced well before the WW2, I don't know of anyone that calls it 'blitzkrieg'.
On a similar theme, 'blitzkrieg' requires quick victory (a la Poland and France). It was Frederick the Great who (again as far as I know) enunciated this principle as 'Ours must be short and lively wars.' in his Instructions to Generals. Blitzkrieg isn't just maneuver, it is quick victory as well.
Interestingly, there seems to be a growing trend in academic thought that the German High Command should have realised they had lost within about 2 months of invading the Soviet Union, and done something about it.
So, no, to me, blitzkrieg starts in the 20th century, and certainly requires the integration of tanks and ground attack aircraft.
(Note: my original post contained the term 'deep penetration' I believe I should actually have said 'deep battle'.)