A House committee was listening to arguments Thursday on a proposal to allow qualified commercial airline pilots to carry guns in the cockpit, but divisions in Congress over the legislation are wide and the bill may not see the light of day.

The Arming Pilots Against Terrorists Act, introduced by Rep. Don Young, R-Alaska, and Rep. John Mica, R-Fla., would allow pilots who volunteer to go through background checks and weapons training to be certified to carry a special gun with bullets that would not pierce the skin of the aircraft.

The House Transportation and Infrastructure Committee Aviation Subcommittee was hearing from supporters who said arming pilots will give flight crews and passengers a last-ditch fighting chance to save their lives if a hijacker were to try to take over a plane. Critics told the subcommittee that the margin for deadly error — or the possibility for criminal misuse — is too great.

Mica said a well-trained pilot with a gun may prevent the Defense Department from having to make the difficult decision to shoot down a commercial airliner because a terrorist has taken it over.

"Under these circumstances, arming crews is a necessary step. Nothing else can provide the effectiveness of a weapon wielded by highly-trained individual," he said.

But Rep. Eddie Bernice Johnson, D-Texas, said pilots need to focus solely on flying the plane and it should be the responsibility of the Transportation Security Administration to improve airline screening procedures to make sure terrorists don't get on the plane in the first place.

Transportation Secretary Norm Mineta and Homeland Security Director Tom Ridge oppose the legislation. Mineta has said guns in the cockpit are not needed because cockpit doors have been reinforced, preventing terrorists from getting control of the plane.

The TSA, operating under Mineta's jurisdiction, is considering whether stun guns or tasers would be a better option for pilots. Both stun guns and tasers give an electrical shock that temporarily incapacitates someone by disabling a person's central nervous system, and giving flight crews the time to subdue a potential hijacker.

The advantage, supporters say, is reduced risk of injury to other passengers and to the airplane. Critics argue, however, that tasers can only fire one shot at a time before the gun has to be recharged, which means if more than one hijacker is bearing down, there won't be enough juice to subdue them all.

Pilots unions are backing the arming of pilots. The Allied Pilots Association has gathered 43,000 signatures in support of allowing trained pilots to carry guns.