Dominion / modern New Zealand
Who & why: the Southern Cross ensign, flown informally for decades, is fixed as New Zealand's own national flag by the New Zealand Ensign Flag Act 1902. Five years later, on 26 September 1907, New Zealand is proclaimed a self-governing Dominion within the British Empire, formalizing an autonomy it had exercised in practice for years. Full practical sovereignty follows gradually across the mid-20th century, marked in law when New Zealand adopts the Statute of Westminster in 1947.
What it represents: the Union Jack in the canton records the constitutional link to Britain that shaped New Zealand's founding institutions; the four red, white-bordered stars of the Southern Cross on the fly mark the country's place in the southern hemisphere, echoing the same constellation flown by several of its Pacific neighbors while remaining distinctly New Zealand's own arrangement and colors.