From this:

CENTRAL IRAQ — At least two Iraqi ultralight aircraft flew over a patch of desert Friday where thousands of U.S. soldiers and several command and control facilities are located. The appearance of enemy aircraft over U.S. positions is especially alarming because the military believes ultralight aircraft of the type spotted Friday may be used to deliver chemical or biological weapons...

Both of the small, prop-driven aircraft spotted here evaded a tight air defense system and flew over an assembly area packed with helicopters, tanks, Bradley fighting vehicles other military equipment. They flew off before the anti-aircraft crews could get permission to shoot them down...

...In December about “half-a-dozen” ultralight aircraft were also spotted flying over two U.S. military camps in Kuwait...

[In other news,] journalists traveling with units in the field were told to stop using a certain brand of satellite telephone. The command is worried that, in some fashion it would not explain, the Iraqis might use signals from those phones to gather intelligence about American operations. The command did not order all phones shut down, just those using the Thuraya satellite. That system is based in the United Arab Emirates and is Arab owned. Other satellite phones, including those in the Iridium system, were not subject to a shut down order. Iridium is an American-owned system.

More info on Thuraya here.