It was the first time the 26-year-old singer was allowed to take Preston, 3, and Jayden, 2, out of California since losing all custody rights earlier this year to ex-husband Kevin Federline.
"This is a terrific indication of the progress she's made, and the growing trust between the two parents," says a source close to Spears. "It was arranged cooperatively between Kevin and the lawyers."
Spears made the trip the day after her mini reunion with former boyfriend Justin Timberlake at a Madonna concert in L.A. Spears traveled with her father, Jamie, who has legal control of her affairs.
Since reaching a custody settlement in July, Spears currently has two visits and an overnight per week with her children.
Adds the source: "Britney just wanted to get some family time in and show the boys Louisiana, now that they're getting older."
Additional reporting by STEVE HELLING and JENNIFER GARCIA