United Airlines confirmed Friday that it is one of several U.S. carriers looking into the possibility of arming its pilots with stun guns.

A spokeswoman stressed that their use would hinge on approval by the Federal Aviation Administration.

"It is something that we're interested in," United spokeswoman Chris Nardella said. "We're working closely with our pilots union. But we've made no decision."

The pilots union has endorsed the idea. United is the dominant carrier at Denver International Airport.

Stun guns would supplement security efforts that include reinforced cockpit doors and other measures aimed at foiling hijack attempts.

Mesa Air Group, which operates America West Express and US Airways Express, announced three weeks ago it planned to train its pilots to use stun guns. Indianapolis-based American Trans Air said this week it has contacted several stun gun manufacturers and plans to make a decision soon.

The Air Transport Association, trade group for the major airlines, opposes the use of lethal weapons by pilots but supports the study of non-lethal devices for crew members, particularly flight attendants, spokesman Michael Wascom said Friday. He said stun guns are "worthy of looking at."

The FAA is currently reviewing its rule prohibiting any deadly or dangerous weapon on scheduled passenger flights. Congress, which has been working to tighten airline security since the Sept. 11 terrorist attacks, also could override it.

United declined to discuss specifics of its stun-gun considerations. But Scottsdale, Ariz.-based Taser International Inc. said this week it had recently been in touch with five domestic airlines about the possibility of supplying stun guns.

Tasers can take down a hijacker from 21 feet away, immobilizing the attacker for five seconds or more, said Steve Tuttle, director of government affairs for Taser International.

Using a laser sight, the Taser shoots a pair of quarter-inch darts trailing wires into the attacker. A five-second, 26-watt shot of electricity contracts the muscles and overwhelms the central nervous system, preventing any coordinated action, Tuttle said.

Airlines are interested in the Taser because it's easy to use and because errant shots won't do permanent harm to innocent passengers or shoot a hole in the plane, he said.