The recent killing of a popular lion named Cecil by an American dentist in Zimbabwe sparked considerable outrage on social media and elsewhere against safari hunting. The event has also brought to light the role that airlines play in transporting trophy kills as cargo, and may have contributed to changing airline policy.

On Monday, Delta Air Lines became the latest carrier to change its rules about transporting hunting trophies. Its announcement came as a group of airlines including Air France, KLM, Iberia, IAG Cargo, Singapore Airlines and Qantas signaled last week they would ban the transport of trophy-hunting kills, according to Paul Ferris, the campaign director at SumOfUs.org, a consumer-based petition agency in Brooklyn, which has pressed for changing cargo policies.

“Airlines and other large travel corporations would be foolish to ignore the public reaction to the killing of Cecil the lion, and growing concern about the plight of endangered species,” Mr. Ferris said.

Such a ban was initiated by South African Airways in April, and Emirates, Lufthansa and British Airways later joined. These airlines pledged not to carry big game trophies, including elephants, rhinos, lions and tigers as cargo.