You’ve always been able to travel with pets in the cabin on US carriers as long as the crate will fit under the seat. I haven’t heard of anyone dying, or even complaining, yet.
Sometime within the last two years, a passenger across the aisle from me on a regional jet had two cats in a cat carrier. She had apparently purchased a seat for the kitty-box, and strapped it in said seat. I don’t recall the airline (probably either United or Air Canada) or whether the flight was within USA or Canada ...
News to me...
The only animals that would fit under seats in planes here would be about 1 pound or so! I am willing to pay for a seat for my dog(20 lbs). He is hypoallergenic. I would hold him as needed. Would be far less of a distraction than a baby. I don’t want him in cargo.