The pilot missing with English Premier League footballer Emiliano Sala is the ex-husband of a woman who lives in New Zealand.
The small plane flown by David Ibbotson with Argentine striker Sala on board went missing on a flight from France to Wales on Monday night.
The search was abandoned on Wednesday, with search and rescue teams saying they held no hope of finding survivors and the operation had become a recovery mission.
The Daily Mail said 60-year-old Ibbotson's ex-wife is Georgina Gymer.
Gymer's sister Linda Goodwin told the Mail that neither of them knew Ibbotson was on the missing flight.
"This is terrible, it's shocking, we had no idea. He is my ex-brother-in-law. I was at the wedding. He and my sister are divorced now but they have two children together. She lives in New Zealand and the kids, who are grown up, are in England. He got remarried."
A man at the Gymer home in Devonport, Auckland, said today that they did not wish to make any comment.
It is thought the missing plane, a six-seater Piper Malibu, may have suffered a build-up of ice on its wings, stalled and crashed into the sea. It disappeared at 8.30pm on Monday while flying over the English Channel.
Sala had just been signed to play for Cardiff City, at a fee of £15 million ($28.9 million), a record for the club. Previously he played for French club Nantes.
Investigators are probing Ibbotson's flying licence. Questions have been raised over the arrangements for the flight because he held a private licence, not the commercial pilot's licence required for scheduled or paid-for flights.
The private pilot's licence allowed him to fly passengers between airports as long as he didn't profit from any journey. If paid a fee amounting to more than his fuel costs and expenses to take Sala between France and Britain it would be classed a commercial flight.
The Daily Mail said Ibbotson had outstanding debts of more than £18,000 (about $34,700). He often flew skydivers to jump sites and belonged to three "ferry flight" Facebook groups where companies advertise flying jobs.