I don't use tennis balls for that reason and because they get popped by other dogs and are the #1 obstruction in dogs GI tracts requiring surgery. My odgs don't tend to pop them or chew them but I'd rather use a safer. longer lasting ball. I love the ones made py planet dog. They are a bit pricey but totally indestructable, last forever, fly great and have a light mint scent so the dogs never lose them even in the winter.
www.planetdog.com click on toys
planet dog also donates a ton of money to animal related charities so I like buying from them.