Airline efforts to corral the menagerie of animals in airplane cabins have fizzled this summer. Delta DAL, +0.20% American AAL, -1.20% United UAL, -0.05% and other carriers tightened requirements on emotional-support animals, trying to curb the dramatic increase in dogs, cats and other creatures flying uncaged with airline passengers. In some cases, 50-pound dogs share space in cramped coach seats with their owners and neighboring passengers.
Delta says it has had six biting incidents in the past 60 days. The airline now carries about 700 emotional-support animals and service dogs on flights each day, up from 450 a day in 2016. The total number of animal incidents on airplanes—from urination to barking to biting—has increased 84% since 2016, says Gil West, Delta’s chief operating officer.
People who rely on highly trained service animals say their service dogs can be provoked by aggressive dogs unfamiliar with airports and airplanes, and people with animal allergies say flights with multiple pets have grown more common, exposing them to more allergens.
In June, a Delta flight attendant was badly scratched by a pit bull and Delta banned that breed from riding in its cabin. “I think we’ve hit a tipping point,” Mr. West says. “We’re very concerned about the safety of our customers and our crew.”
Last year, the number of pets carried by U.S. airlines (usually for a fee in the cabin or cargo hold) increased 11% to 784,000, according to Airlines for America, the industry’s lobbying organization. The number of service animals increased 24% to 281,000, according to A4A. And the number of emotional-support animals leapt 56% in that one-year period, to 751,000.