The government-funded New Zealand study into the flight raises questions about the safety of international travel during the pandemic, even when the precaution of pre-flight testing is taken.
The infections occurred on a flight from Dubai to New Zealand in September.
In total, seven cases from the flight were identified in managed isolation and scientists believe that four of those cases picked up the virus during the 18-hour flight.
There were 86 passengers onboard the flight.
Those seven passengers came from five different countries before travelling on the flight from Dubai, but genomic testing suggested that four infections took place onboard as they carried genome sequences from Switzerland, the country of origin of the source case.
That source case had tested negative on a polymerase chain reaction (PCR) test 48 hours before their flight.
"These seven cases were found to have been seated within four rows of each other during the approximately 18-hour flight," the NZ study states.
"Recent studies have presented conflicting findings of the risks associated with in-flight transmission. We therefore undertook a comprehensive investigation to determine the potential source of infection."
