Jessica Alba and her husband Cash Warren flew in coach while their kids lived it up in first class.

The couple share daughters Honor, three, and 11-month-old Haven together.

When the family boarded a Virgin America plane to New York City Tuesday, Jessica and Cash shocked everyone.

As the parents nestled into their coach seats, jaws dropped as travellers witnessed Honor and Haven join their nanny in the luxury section.

"Everyone was doing a double take, seeing Jessica Alba sitting in coach, while her kids and nanny were in first class," a passenger told Radar Online.

Jessica and Cash weren't far away from their tykes.

When baby Haven cried, Cash gave Jessica a break and took on the role of nurturer.

"Cash was such a doting dad, walking Haven up and down the aisle during the flight," the source recalled.

"It was really cute."