Should Fido Fly? You May Not Like the Answer Time to reconsider taking your pet along on the next family vacation.

Sept. 27, 2012 -- On the heels of two pet death incidents – both on United Airlines – it may be time to reconsider taking your pet along on the next family vacation.

Michael Jarboe's dog, a two-year-old Neapolitan mastiff named Bam Bam, died on a cross-country United Airlines flight last month. And earlier this month, cover model Maggie Rizer drew national attention to the issue of pets on planes with her blog post, "United Airlines Killed Our Golden Retriever."

And the Department of Transportation is considering new rules for airlines when it comes to transporting pets. Today is the last day the DOT is hearing public comment on the issue.

There are three major changes proposed. First, the new rules would expand the reporting requirement to U.S. carriers that operate scheduled service with at least one aircraft with a design capacity of more than 60 seats. Currently, only 15 airlines report animal losses, injuries and deaths.

Second, the rules would also expand the definition of "animal'' to include all cats and dogs transported by the carriers, regardless of whether the cat or dog is transported as a pet by its owner or as part of a commercial shipment, such as a breeder.

According to the Humane Society of the United States, currently only owned pets are reported on. So if a breeder is transporting a cat or dog that dies, it does not have to be reported.

Third, the new rule would require carriers to provide annually the total number of animals that were lost, injured, or died during air transport for the calendar year. This would include exotic animals being transported between zoos.

Kirsten Theisen, director of pet care issues for the Humane Society of the United States, told ABC News the organization fully supports these new measures. "Right now, it's still a bit of a mystery," she said, referring to the current regulations on airlines transporting pets. "We would like to see on those numbers. If the public had access to full spectrum of info they would be a lot smarter if they decide to fly their pet."

"There's a common misconception that if you put your pet in the cargo hold it will be treated like a passenger, but that's not what's playing out in reality," she said. Since each airline individually sets the standard for transport, it's unclear what the temperature control and air pressure control will be. "They're [the animals] packed in with the suitcases and what we've heard is that the suitcases are packed around them to help stabilize the crate, so it's unclear how much air the animal is getting."

While the organization welcomes more regulation, they advise against flying with your pet. "Air travel is a risk to your pet's health and well being," she said. "Our goal is to promote the health and well being of animals and these two things are not compatible."

Flying with your pet, she said, should be a last resort when there is no other option. They're far better off, she said, with a pet sitter or in a kennel than on a plane.

Some pets are better suited to flying than others. Brachycephalic -- or smush nose -- dogs and cats such as bulldogs, Persian cats, pugs and mastiffs have more trouble breathing than other breeds and therefore may not be able to regulate their body temperature well. These animals should "never fly, period," Theisen said. "End of sentence."

Bam Bam, the Neapolitan mastiff that died on a United flight recently, was a Brachycephalic.

In a statement to ABC News, United Airlines said, "We have been in contact with Mr. Jarboe and are saddened by the loss of his dog, Bam Bam. The safety of the animals we transport is always considered first and foremost when making decisions regarding their routing and carriage."

At the time of the death of Maggie Rizer's dog, the airline said, "We understand that the loss of a beloved pet is difficult and express our condolences to Ms. Rizer and her family for their loss. After careful review, we found there were no mechanical or operational issues with Bea's flight and also determined she was in a temperature-controlled environment for her entire journey. We would like to finalize the review but are unable until we receive a copy of the necropsy."