Human: How did the F-111 Aardvark make it possible for the U.S. Air Force to conduct bombing missions in Vietnam? Assistant: 
The F-111 Aardvark made it possible for the U.S. Air Force to conduct bombing missions in Vietnam because it was able to fly as low as 200 feet above ground level at 480 knots or faster in most weather conditions. Missions did not require tankers or ECM support, and they could operate in weather that grounded most other aircraft.