The Department of Transportation estimates that more than 2 million animals fly each year in passenger cabins and cargo holds, but little is known about how they fare.

After years of mixed messages about the wisdom of shipping pets in the cargo hold of planes, pet owners will finally get a clear answer this summer, thanks to a new federal rule that requires airlines to report incidents of animal loss, injury or death.

Starting June 15, airlines must report such incidents to the U.S. Department of Transportation, which will make the data public through its monthly Air Travel Consumer Report, available online at: airconsumer.ost.dot.gov/reports.

It is estimated that 1% of animals (that fly) are lost, injured or killed.

The Humane Society discourages owners from bringing pets on planes unless absolutely necessary. They recommend going by car if traveling with pets (neither Amtrak nor Greyhound allows pets) or leaving pets at home with a pet sitter or at a boarding kennel.

Links: USATODAY, Pet Travel in the U.S.