This week, helicopters came under scrutiny following an FBI alarm that they might be used by al Qaeda in terrorist attacks. The FBI and the Department of Homeland Security sent the alerts last Friday night to 18,000 police and government officials, the Associated Press reported yesterday. Security was tightened at heliports in New York City and elsewhere, but reports said that some officials were skeptical of the substance of the alerts and questioned whether they were based on any credible or current information (we love an election year). Federal officials also required heliport operators to turn over details about employees for background checks. "We remain concerned about al Qaeda's continued efforts to plan multiple attacks against the U.S., possibly employing general aviation aircraft, including helicopters," the FBI directive reads, according to an unnamed source cited by the New York Daily News. The FBI also said that al Qaeda may use helicopters to spread chemical or biological agents, the Daily News said. The alert also cited limos as possible delivery systems of terrorist weapons. No word on whether rental trucks, dinghies or wolves in sheep's clothing were also cited as possible threats.