The star couple was left traumatised after Mendes was originally due to fly on a plane that was hijacked and crashed into the Pentagon on 9/11, according to British newspaper the ‘Daily Mail’.
All 64 passengers and 125 people in the U.S. government building in Washington D.C. were killed - but Mendes had changed his plans and hadn't boarded the aircraft, reports ‘Contactmusic’.
Winslet endured a similar scare just a month later.
The 33-year-old was on a British Airways flight from London to Dallas when a man stood up and shouted that he was an Islamic terrorist and they were all going to die.
The man was arrested after the plane landed but Winslet remains cautious about air travel.
She married Mendes in 2003 and the couple have agreed never to fly together, to ensure that their son Joe and Winslet's daughter from her first marriage Mia are never left without both parents.
A spokesperson for the couple says, "Where possible, Kate and Sam do prefer to travel in separate planes. It is not always possible but, for obvious reasons regarding the children, they do travel separately when they can."
