London’s Heathrow Airport welcomed fully vaccinated travelers arriving from the United States and most parts of the European Union Monday, the first day they could do so without going into quarantine.Heathrow Chief Executive John Holland-Kaye called lifting quarantine rules “a milestone,” saying it has allowed families to reunite that have been kept apart by the COVID-19 restrictions for as long as 18 months. Video from the airport Monday showed several emotional family reunions.New arrivals must still be tested before boarding their flights and take genetic polymerase chain reaction (PCR) COVID-19 tests within two days of arrival.Holland-Kaye has urged the government to “keep it simple” and to find an alternative to expensive PCR tests.The delta variant of the virus, first detected in India and currently surging in Britain and elsewhere, has added to uncertainties around international travel. But Holland-Kaye said vaccinated travelers coming into Britain — where more that 72% of adults have been fully vaccinated — will build confidence in the vaccines and perhaps convince unvaccinated people to get vaccinated.Britain is maintaining quarantine requirements for French travelers, prompting objections from some French officials.British government officials say France has a concerning number of cases of the beta variant in some provinces and territories but added that they plan to review the policy later this week. The beta variant was first detected in South Africa.