You can have it framed using acid free backing and and a special grade of glass (UV protection) that will help prevent fading. Have a picture done like that and its worth the cost. Any good framing shop should tell you what you need. I wouldn't worry too much about the wrinkles.
A high quality framer could sandwich it between two pieces of museum or conservation quality glass and then you could see both sides of the flag. Get it framed properly, it won't be cheap.
Hang it out of direct sunlight.