Heartbreaking new details have emerged after an Australian family was killed in a plane crash in the United States, including the reason their only surviving daughter wasn’t on the flight with them.

Queensland man, Christian Kath, 42, his wife Misty, 43, and their 12-year-old daughter Lily were flying over the Gulf of Mexico on Saturday night local time when their plane crashed into the water.

Venice Police Chief Charlie Thorpe told reporters on Monday that the plane was rented by the family from St Petersburg, Florida, on Saturday afternoon, with Mr Kath flying his wife and daughter to Venice, Florida, for a sunset dinner.

However, alarm bells rang when the family failed to return the rented aircraft, sparking a police search just after 10am on Sunday.

Around the same time that the search began, recreational boaters found the body of Mrs Kath floating in the water, about 4km off the coast of Venice.

The 12-year-old girl’s body was found inside the aircraft a few hours later.

Mr Kath has still not been found but is presumed dead, with police calling off the search for the missing man.

The couple’s other daughter, aged 10, was at a sleepover at the time of the accident which is why she wasn’t on the plane with her family.

It has now been revealed that the surviving daughter will move in with her grandparents, Mrs Kath’s parents, Penny and John.

A GoFundMe page has been set up by one of Penny’s friend’s, Leah Hargraves, who revealed the family was planning to move back to Australia in a matter of weeks.

“Penny’s family (originally from Australia) were due to come back to Australia this summer where the two girls were supposed to start school,” Hargraves said.

Mrs Kath’s parents had also just moved from Hope Island on the Gold Coast to Wellington Point in Brisbane to be closer to the family when they returned.

 “What started as a fun afternoon to rent a plane and fly down somewhere for dinner has resulted in absolute tragedy,” Hargraves said.

“Now Pen and John will be both parents and grandparents to their only surviving 10yr old granddaughter in the next couple of days.”

The friend noted that while money wasn’t going to “bring them back”, it would help John and Penny provide for their granddaughter and the “known and unknown necessities they are about to undertake”.

More than A$2300 has been donated to the fundraiser.

Mr Kath’s father, Chris, who lives in Gympie, Queensland, told 7 News that the little girl had expected her parents to pick her up on Sunday.

“She was trying to text and call her mum and sister in the morning, [asking] when were they coming to pick her up,” Chris said.

He said he received a call on Sunday from one of his son’s friends informing him that “something was wrong in Florida”.

Christian Kath is still missing, presumed dead, while Misty Kath's body was found in the water. Photo / Supplied

He immediately tried to call Mr Kath but couldn’t get through, before managing to contact a local police officer who was able to tell him what had happened.

Chris told the publication that police informed him Mrs Kath had been found “floating face down in water” by boaters on Sunday morning.

“Lily was still in the back of the plane … The plane had broken up on impact,” he said.

Chris said his son and his wife had a “lovely family” with the group having previously lived in Brisbane, the Gold Coast and Forbes in NSW.

The family had been living in the US for five years, with Mr Kath being the COO of clinical waste solution company Daniels Health.

The Gympie Times reported on Wednesday that the family was planning to return to Australia soon.

“I want Christian to also be remembered for his depth of character as well as his loving character,” he said.

“He really will be missed. The world will be a poorer place for not having Christian.”

Haunting post before plane crash

A Facebook post from Mr Kath, months before the tragic accident, revealed he had only recently started flying planes.

On March 22, he uploaded a series of photos to celebrate “flying solo” for the first time since starting lessons in late December 2021.

At the time of posting he said he was “about halfway through” getting his private pilot’s licence.

“I flew solo for the first time today! Felt so proud to finally achieve something I’ve been wanting to do since I was eight years old,” he wrote.

“Thanks for putting up with my early morning lessons and late night studying Misty Kath; it will all feel worthwhile when we can fly to the Keys for a weekend away.

“Feel lucky to live and be learning to fly in such a beautiful part of the world!”

Christian Kath, with his wife Misty Kath, had recently gained his pilot's licence. Photo / Supplied

Chris told 7 News he had been on a flight piloted by his son when he went over to visit the family in March.

He said while Mr Kath hadn’t had his licence for long, he didn’t believe he would have deliberately taken any risks while flying his family.

“Christian was not a risk-taker in any way, shape or form – and not one to push the boundaries in that sort of way at all,” he said.

“He wasn’t doing anything that he should have done.

“Having said that, he didn’t have years of flying experience. He wasn’t a long-time, seasoned pilot. He was relatively fresh, you can say.

“Who knows what went wrong – if it was pilot error, and I’m acknowledging that it possibly was …

“But it’s just one of those things.”

Local police recently told reporters it was not yet clear what caused the plane crash.