Seven million people worldwide are going on holiday without travel insurance, according to an NOP survey for American Express.
It finds that 45% of British holidaymakers book their holidays at the last minute, and 55% take a new policy for each trip they make.
American Express head of insurance services Sue Harper said: "People booking last-minute holidays are eager to save money, but often overlook the fact that savings reaped from cheap breaks are wasted if they do not have flight cover."
On average holidaymakers pay £92 per trip for their family's travel insurance, while annual travel insurance costs less than £100.