Maybe you’ve noticed. I don’t hyphenate. To me, it’s postwar. Just why and how Americans eliminated the hyphen and scrunched the words together, I have no idea. It may come from the American habit of simplifying usage whenever we can.
The Oxford Dictionary tells me the British way is post-war. That’s fine, except that I don’t like hyphens if you can get rid of them and the word flows better. A hyphen is like a stutter in the middle of a word. In this case, it’s not needed.
But I’m not British, and I can do what feels natural. Many of you readers out there are British or use British spellings. I just wanted to let you know I’m not doing it wrong, and neither are you.