Travel experts and airlines across the world are constantly brainstorming ways to make travel safe again. As more research comes out about COVID-19, businesses are using the findings to figure out how to get back to some sort of safe normal.

Delta Airlines CEO Ed Bastian stated on a call recently that the airline is open to anything that will make travelers feel comfortable getting on a plane again. That included the idea of requiring an immunity passport before boarding.

An immunity passport is a document that shows proof that a person has the necessary antibodies to fight off the virus. This is mostly present in people who have already contracted the virus and recovered.

“We will make whatever changes to the business model that will be necessary,” Bastian said on the call. “If it turns out immunity passports will be a new form… You think about everything that came out of 9/11 with TSA and homeland security and new public agencies. Could there be a new public health agency coming out that requires a new passport to travel? We’ll be on the forefront of all those advances.”

Countries like Chile, have already begun issuing the immunity passports and are allowing those with the document to break lockdown rules already in place and return to normal life where possible.

Researchers in the United States are not totally sold on the findings that antibodies are an indicator that the virus won’t come back.

“We do not know enough about the new coronavirus yet to determine whether survivors are really immune,” the Infectious Diseases Society of America said on Twitter. “COVID-19 is such a new disease that there is no solid data on the immunity of survivors.”

The World Health Organization warns that issuing immunity passports could actually do more harm than good. They believe that people with the documents will ignore health measures put in place that protect those who have not gotten the disease, which could, in turn, lead to a spike in cases. There is also concern that people will intentionally try to contract the virus so that they can “recover” in hopes of getting their documents issued for travel.

Either way, whenever we return to travel we can expect several new policies to help protect our health and safety.

Related: Jetlue Is The First U.S. Airline To Require Passengers To Wear Face Masks