My wife just recently became a PR. We are still waiting for her card to be mailed, but had a pre-planned trip to Hawaii booked in a couple of weeks. Can she still travel to the US and return without having the PR card? Our concern is that she wont be let on the plane back to Canada from Hawaii. She does have Nexus as well if that makes a difference but I have seen some conflicting information online so wanted to confirm if this is possible.