Just when did various nations adopt the various cross and cockade or roundel
insignia? Was it after WW1 started and the need for recognition became
apparent or did some nations adopt an insignia before WW1?

When did the US adopt the Star with a dot insignia? I know that they used a
roundel style similar to the French style in WW1 while in Europe. Did US
aircraft based stateside use the same insignia as the European combat aircraft
or did they use the star?

John Dupre'