Until this week, people who carried a pet into the cabin — which involves paying a $150 fee — could only have one other small item that fit under the seat.

Anything bigger, like a carry-on bag with wheels, needed to be checked — for a $35 fee. Or they could put the pet in the cargo hold.

Now American is letting passengers bring a pet in the cabin and also bring a regular carry-on bag or a personal item — just not both bags.

The old policy struck some pet owners as unfair, since they were already paying a pet fee.

Gary Leff, a travel blogger who first wrote about the change, recalled traveling years ago with a Yorkshire terrier.

“It was always frustrating that the dog counted as the carry-on even though I was paying the extra (pet) fee that was sometimes more than the ticket for me,” he said Friday.

Leff said he thinks American’s change will reduce the urge for travelers to falsely claim that their pet is a service animal that flies for free.

An American spokeswoman confirmed that the rules change took effect Thursday.

“We made the change to provide a more convenient and comfortable experience to customers whose pets fly American,” she said.