Jessica Simpson explains why kids sat apart on Hawaii flight reunion

Jessica Simpson clarified why her three children were seated apart from her on a recent flight to Hawaii, where she unexpectedly crossed paths with ex-husband Nick Lachey.

The 45-year-old singer revealed that her mother, Tina Ann Simpson, purchased the tickets as a treat, which resulted in her kids, Maxwell “Maxi” Drew, 14, Ace Knute, 12, and Birdie Mae, 7, being booked in a “separate class of service.”

“My mom bought those tickets. It was my mom’s treat for us to go to Hawaii,” Simpson told photographers on May 10.

Asked if her children would have been seated with her had she purchased the tickets herself, she replied, “Of course!”

Lachey previously recounted the encounter on Watch What Happens Live with Andy Cohen, noting that the families “spent six and a half hours on a flight to Hawaii together.”

He clarified that “spent” meant being in the same vicinity, as Simpson was accompanied by her mother while her estranged husband Eric Johnson and their children were seated elsewhere.

Lachey described the experience as “strangely okay” and “honestly fine,” despite not having seen Simpson in 20 years.

A source previously told PEOPLE that Simpson, Nick, and his wife Vanessa Lachey shared a “very amicable and cordial” conversation during the flight.