Alternate history:
1) Some later stage of Operation Unthinkable, maybe 1946: RAF and USAF against the Soviet Union, optionally with german involvement (and copies of german jets or early Red Air Force jets fighting on the other side).
2) Operation Downfall, with a handful of japanese jets thrown in.
3) "Who's the phony now?": French and british invasion of the Reich in september 1939.
4) "No Appeasement": Air combat over the Czechia in 1938.
5) "Kein Anschluss unter dieser Nummer" (pun; "No connection for this number", with "Anschluss" having a double meaning as a short form of "Telefonanschluss" (phone connection), as well as the propaganda term for the takeover of Austria: "Anschluss Österreichs (an das Reich)"): Austrian opposition against hostile german takeover ambitions 1938.
6) "Garde du Rhin": French military opposition against german remilitarization of the Rhineland 1936.