Your wife would only have permission to fly if she has a confirmed job in Canada. Otherwise she needs to be included in the letter.My wife and I have already been approved for travel. My kids are the ones who need the letter. We were told by the immigration officer when we tried to travel last week. They already showed our documents to a Canadian liaison officer and was advised to get a letter for my kids. Since our travel is essential and we can't leave our kids alone, we should be approved in principle.