Enzo died while traveling in the cargo hold. A pathology report said heat stress was the likely cause of death, exacerbated by the dog's advanced age and mild obesity.
TWA offered the couple $1,250 - the amount of liability that airlines are required to pay for lost or damaged baggage. The couple has sued.
Citing disturbing stories like these, some lawmakers and animal advocates say that dogs, cats and other pets that fly in airplane cargo areas deserve stronger protections against rough handling, temperature extremes and oxygen depletion.
"Some of these cases are awful, in terms of the torture they put the animals through," said Sen. Frank Lautenberg, D-N.J.
Lautenberg is sponsoring legislation that requires airlines to train their baggage handlers; doubles to $5,000 the maximum penalty the federal government can impose on an airline; increases the amount of money a pet owner can recover if an animal is lost, injured or killed; and requires that airlines compile and release information on animals hurt or killed.
The legislation also requires airlines to improve air flow and climate control in sections of airplanes where animals are kept.
The airline industry says the proposed protections are unnecessary and burdensome.
Michael Wascom, director of government affairs for the Air Transport Association, predicted that some airlines would "simply stop accepting live animals" rather than increase training of baggage handlers, adjust climate control on airplanes and face greater legal liability in case something goes wrong.
The Senate approved the proposals as an amendment to the Federal Aviation Administration reauthorization bill, but a companion bill proposed by Rep. Bob Menendez, D-N.J., failed in the House, leaving the issue in the hands of a House-Senate conference committee.
One member of the conference committee, Sen. Slade Gorton, R-Wash., has proposed an alternative -- a study of the issue by the General Accounting Office, Congress' investigative arm.
The Humane Society of the United States supports stronger protections for animals, contending the airline industry "treats live animals as mere baggage, transporting them in cargo holds not designed for life support."
The American Kennel Club, however, citing "too many unanswered questions," is urging defeat of the Lautenberg bill until congressional hearings are held on it. The club, which has worked with federal agencies to make air travel safer for dogs, fears airlines would respond to Lautenberg's measures by refusing to carry animals.
The Air Transport Association has reported that "more than 99 percent of the estimated 500,000 dogs and cats that airlines handle each year reach their destination" without incident.