Police pulled over a tractor-trailer loaded with anti-aircraft missiles on an Ontario highway Friday. Several police cruisers were needed to pull over the vehicle on Friday as it traveled westbound on Highway 407, near Toronto and its international airport. The Canadian Army was investigating the incident. The trailer was carrying two armored personnel carriers bearing Canada's Department of National Defense license plates and loaded with anti-aircraft missile launchers. Police say the carriers, formerly registered to the Princess Patricia's Canadian Light Infantry, were supposed to be delivered to Montreal on Thursday. A spokeswoman for the Department of National Defence said the army was investigating.