TAMPA — Officials say at least six passengers fell ill on a Frontier Airlines flight from Cleveland to Tampa.According to published reports, the passengers who traveled on Tampa-bound Frontier Airlines Flight 1397 on Tuesday fell ill after leaving Cleveland Hopkins International Airport.Officials say they are being held for observation. The sick passengers on board the flight to Tampa International Airport were not traveling together.The passengers were said to be vomiting by the time the plane landed, according to reports. Several water fountains were shut down at Cleveland Hopkins International Airport after the passengers became sick, according to reports, although airport officials could not confirm that was the cause of the sicknesses.The remaining passengers were kept on the plane for about an hour after it landed. Those passengers deplaned around 4:30 p.m.This is a developing story. Stay with tampabay.com for updates.