What happens if there is a sick passenger on my flight?
Under current federal regulations, pilots must report all illnesses and deaths to CDC before arriving to a US destination. According to CDC disease protocols, if a sick traveler is considered to be a public health risk, CDC works with local and state health departments and international public health agencies to contact passengers and crew exposed to that sick traveler.
Be sure to give the airline your current contact information when booking your ticket so you can be notified if you are exposed to a sick traveler on a flight.
For more information: Contact Investigation
See also: Traveling