Spanish Flu symptoms (information from About Education http://history1900s.about.com/od/1910s/p/spanishflu.htm)
The victims of the 1918 Spanish flu suffered greatly. Within hours of feeling the first symptoms of extreme fatigue, fever, and headache, victims would start turning blue. Sometimes the blue colour became so pronounced that it was difficult to determine a patient's original skin colour. The patients would cough with such force that some even tore their abdominal muscles. Foamy blood exited from their mouths and noses. A few bled from their ears. Some vomited; others became incontinent. The Spanish flu struck so suddenly and severely that many of its victims died within hours of coming down with their first symptom. Some died a day or two after realizing they were sick.
With the Spanish flu being a air born virus the vehicle that would best fit it would be some sort of flying vehicle. The symptoms that stick out the most to me is the skin turning blue and the foamy blood exited from the mouth and nose and bleeding from the ears. With the Spanish flu spreading so fast it would make sense that this vehicle would be the fastest one or have some sort of speed boost, this speed boost could be portrayed in a style of the vehicle sneezing. The ability of this vehicle be the speed boost and a foamy blood spray that blinds the vehicle behind you.