It doesn't exist any more, much like our colonial ties to Great Britain, and hopefully one day, the symbolic monarchy in the Canadian government. The United States created their own flag after independence, so I'm surprised by your attachment to the red ensign.
The Red Ensign has a history to it. IMHO the Maple Leaf flag does not represent Canada's history.
The maple leaf itself has been part of Canadian society for over two centuries. You can find it plastered on documents long before the red ensign became Canada's flag. It is a uniquely Canadian symbol, unlike the union jack. The red ensign was created in 1707. It was a merchant navy flag and it is not unique to the country of Canada. It was simply slapped onto the country by the British.
The Red Ensign was still Canada's flag in 1931 when you gained your independance from Britain and Canadians fought WWI, WWII and in Korea under the Red Ensign.
It just took Canadians longer to change their flag after independence. As far back as WWI, every battalion had the maple leaf in its insignia. That was the symbol for Canada. And red and white were the official colors of Canada since 1921. The only reason the red ensign wasn't replaced earlier was to not offend the British. Just recall how the British shreiked when Australia suggested removing the monarchy a few years ago.