Attended a court hearing, the Judge/Commissioner said that I absolutely had the right to travel with my child out of country, despite the opinions of the other parent. Something along the lines of, "some people think this is a dangerous time to travel while others think this is a good time to take advantage of travel deals. It is not my place to decide which is correct since there are no provisions in the parenting plan already"
And like that, we went on our trip and had a great time that helped the visiting communities with our travel. And everyone returned home with no illness.
Also, the courts put it in writing. But really, id didn't matter because no airline checked for anything at all and it was travel like normal. We flew both Delta and Aeromexico. But again, no airline at any time questioned anything, both leaving the US, boarding in Mexico to fly within Mexico, or when leaving Mexico headed back to the US
consult with a good lawyer.