The Reagan administration's drug policy board is considering whether the U.S. Customs Service and Coast Guard should be allowed to shoot down airplanes suspected of drug smuggling if their pilots ignore orders to land.

The National Drug Policy Board is weighing the controversial proposal to permit Customs and the Coast Guard "to use appropriate force" to "compel a suspected smuggling aircraft" to land, according to an "issue paper" obtained by The Washington Post.

"Such authority would authorize the firing of weapons as a warning and, if necessary, to fire into the aircraft to ensure compliance," the paper states.

The Cabinet-level board is to vote early next year on the proposal, which is backed by Customs but has been opposed by the FBI, the CIA, the Drug Enforcement Administration and the Department of Transportation, according to a senior Justice Department official. Associates described Attorney General Edwin Meese III, who chairs the 17-member drug policy panel, as "less than enthusiastic" about the plan.

Proponents of the measure argue that efforts to stem drug smuggling have been stymied by smugglers who drop drugs from the air or make brief landings, ignore orders from authorities to land, and safely make their way across the border. "As a result, the smugglers are able to operate with virtual immunity from apprehension," the issue paper states.

Others on the panel question the wisdom of the plan, contending that it could endanger the lives of innocent civilian pilots in the event of a mistake or if undercover agents are aboard drug-smuggling planes.

"Everybody thinks it's a hoot," said a senior Justice Department official. "I knew this would come back and bite us . . . if it ever came out. It's absolutely crazy. We need an 'Oops' clause to specify how many we can shoot down by accident each year."

Another administration official added, "Anyone who even raises something like this should have his head examined."

Officials opposed to the proposal argue, among other points, that it would conflict with the United States' claim that the Soviet Union's downing of Korean Air Lines Flight 007 in 1983 violated international law.

Following the KAL shooting, the United States supported an amendment to international aviation rules making clear "that every state must refrain from resorting to the use of weapons against civil aircraft in flight and that in case of interception the lives of persons on board and the safety of aircraft must not be endangered."

In addition, the FBI and DEA have objected to the proposal on the ground that standard law enforcement practice prohibits shooting at a fleeing felon.

As set out in the proposal, the planes would have to be seen "dropping or transferring bundles," presumed to be narcotics or other contraband. Federal aviation regulations permit objects to be dropped from aircraft so long as it is done safely.

The planes could be shot at only when "a higher authority" has approved the firing, and when "all other means of compelling compliance have been exhausted." Although the plan specifies that planes would be shot at only when they are over water, a senior law enforcement official familiar with the plan said it would also apply to planes flying over nonpopulated areas.

The official, who favors the plan, said agents would use radar to track planes entering the United States from overseas and contact the pilots over the radio or with flash cards if their radios are not on. Pilots are not required to have radios unless they fly into specified high-traffic areas.

If the planes fail to heed orders to land, the official said, agents will fire warning shots -- probably using machine guns -- in front of the plane. If this fails, they would then fire into the plane, attempting to disable it in such a way that it could still land.

"We don't want to flame them out of the skies," the official said, adding that the plan might not have to be put into practice often. "In my mind, the mere fact that we even have this on the books is a deterrent," the official said.

Customs Commissioner William von Raab, who is described as the chief proponent of the plan, was unavailable for comment. Lt. Cmdr. Mark Wolfson, a Coast Guard spokesman, said he had no specific information about it.

Associate Attorney General Stephen S. Trott emphasized that although officials are intent on finding a way to pursue drug smugglers who drop bales with thousands of pounds of cocaine or other drugs, they are highly sensitive to the need to protect other aircraft.

"There's no way that the drug policy board will adopt anything that in the slightest way endangers innocent civilian aircraft," he said. "That's not going to happen."