<p>I’ve been fine with United… I don’t know what their policy is, but at 13 I was able to make an international flight from Edmonton, Alberta to New Orleans [through Denver] without a hitch. I was 14 all year without a problem, besides the odd customs official that seemed a bit perplexed at why I was traveling alone and going off to school at 14… but I always have papers with me [copies of my birth certificate, my parents’ work visas/drivers’ licenses, etc.], so issues were always resolved quickly.</p>