In an effort to lure customers back to international flights, United Airlines will start offering rapid COVID-19 tests at Newark Airport for select flights to London.

Passengers on the 7:15 p.m. flight, which leaves on Mondays, Wednesdays and Fridays, will be required to take the rapid test at the airport. The return flight does not offer the same test.

Children under 2 years old will not be required to take the test, and passengers that refuse will be placed on another flight.

The CDC and others have found air travel is not a major source of coronavirus transmission, because of the frequency of air circulation on flights. However, there is still risk due to the long security lines at airports, where passengers stand in close proximity while on line for screening. And with International flights down 92% worldwide compared to last year, United and others airlines hope rapid testing will increase travel numbers by making passengers feel safer.

“The key to restoring the freedom of mobility across borders is systematic COVID-19 testing of all travelers before departure, “ the International Air Transport Association [IATA] wrote in a statement last month. The group is calling for “the development and deployment of rapid, accurate, affordable, easy-to-operate, scalable and systematic COVID-19 testing for all passengers before departure as an alternative to quarantine measures in order to re-establish global air connectivity.”

United is piloting a similar program in Hawaii and San Francisco now. The airline reports a 95% increase in passengers after the testing program launched.

In July it began screening flight crews in Hawaii with the rapid test as well.

In Germany, Lufthansa began offering rapid Covid tests this month for intercontinental first class and business travellers.

Port Authority workers at all three regional airports and the PATH train have had access to free Covid tests since May.

For now, United will cover the cost of the test for the Newark to London flight, but it charges passengers for the tests at the Hawaii and San Francisco airports. A spokesperson says if it's cost effective and brings passengers back, tests could roll out at other major airports around the country.

If a customer does test positive at their screening before boarding the flight to London, United says the passenger will “not be able to fly and should contact their local healthcare provider. Following CDC guidelines, United will re-accommodate a customer once they test negative and no longer are symptomatic,” a spokesperson said.

At a press briefing on Tuesday, Mayor Bill de Blasio called for a federal mandate prohibiting travelers from flying “unless they can prove they’ve had a recent negative COVID-19 test result.” While the mayor praised airlines for beginning to conduct pre-flight testing, de Blasio said, “We want to go farther. We want to make it easy and clear that anyone coming off a plane should immediately get tested as well. We know testing has made all the difference. Why don’t we use that tool that we know works to protect people who travel and protect all of us?”

The Port Authority of New York and New Jersey, which runs Newark, LaGuardia and JFK airports, didn’t respond to questions about whether other airlines will be rolling out testing at their airports, or comment about United’s testing program.