The development of aircraft created many revolutionary changes in warfare which made ww2 very different from earlier conflicts.
The greatest fear of the pre-ww2 leaders of Britain and France was the possibility of attacks on cities and that fear may have caused them to abandon Czechoslovakia at Munich in 1938. When war came, attacks on cities did not immediately achieve the expected effect. However, eventually attacks on Hamburg on 1943 and Tokyo in 1945 approached pre-war expectations and the attacks on Hiroshima and Nagasaki showed that air power could decide a war by 1945.
Germany had placed more emphasis on close support of the army than Britain and France. In May 1940 this was critical for the Germany victory over France. "The Blitzkrieg Legend: The Campaign in the West, 1940" by Karl-Heinz Frieser
The Blitzkrieg legend: the 1940 campaign in the West - Karl-Heinz Frieser, John T. Greenwood - Google Books gives information on the Battle of Sedan especially pages 157-160. Later, for example in Normandy in 1944, Allied close support would be decisive.
The German invasion of Crete in 1941 showed that airborne forces could win victories alone but at a high cost. Surrounded forces could also sometimes be supplied by air. The Demyansk pocket was supplied by the Luftwaffe but Stalingrad could not be supplied. The British forces at Imphal were successfully supplied. However, the biggest supply operation was that over "the Hump" from India to China.
Airpower also became decisive at sea. The Germans could not have taken Norway without the Luftwaffe. Taranto and Malta illustrate its importance in the Mediterranean. Pearl Harbor, Coral Sea and Midway showed that aircraft were critical in the Pacific. By 1943, aircraft, both land based and from escort carriers, were critical in defeating the German U-boats.
Of course, I wouldn't want to spoil your chance to do research. Try to understand peoples fears in 1938 by looking at pre-war predictions. To see the difference between 1939 and 1945, you can look at the difference in the load carried by a B-29 and a 1939 bomber and also look at their ability to find a target in the dark. You may also want to understand what a firestorm was. For the close support issue, you can look at why Sedan was important and also find out what happened at St. Lo and Mortain. Similarly, find out about the naval battles.
Good luck!