Researchers looked at people catching flights from the US to Heathrow between November and March.
The experiment, which involved data from almost 600 travellers on flights from the US to Heathrow, also showed passengers would be happy to pay for their own tests.
Researchers at the Oxford Internet Institute (OII) used flights operated by British Airways and American Airlines for the trial.
Travellers took a PCR test 72 hours before departure, a LAMP test upon arrival at Heathrow – a type which returns results more quickly than the PCR – and a third PCR taken three to five days after returning.
According to the researchers, just one per cent of travellers who took the first PCR tested positive and so did not travel, and none of those who touched down in the US tested positive, suggesting the first test was effective.
Of the travellers who took the third test after arriving in the UK, 0.4% of travellers tested positive.
In a joint statement on the findings, American Airlines, British Airways and oneworld said: “The trial findings underline the important role that testing can play in the safe reopening of international travel, including hugely significant routes between the US and UK.”
The airlines said they would be ready to partner with governments to offer affordable testing options, adding the study “further reinforces that customers are willing to undergo testing as an alternative to quarantine”.
Some 99.7% of travellers said they were happy to adhere to testing requirements as an alternative to quarantine after international travel and 80% were prepared to pay for affordable testing.
The majority were prepared to pay £35 or less for each test, and 15% said they would pay more than £70.
Findings of the Oxford study will be shared with governments and stakeholders.
Professor Philip Howard, professor of internet studies at the OII, said: “As many countries make progress on vaccinating their citizens the debate over reopening travel safely is becoming increasingly important.
“I’m pleased our team has been able to make a contribution to this discussion through this detailed analysis of passenger sentiment and behaviour.”