WATCH: Fauci says plan to require proof of vaccination for domestic travel ‘is on the table’

"Do we know that the virus travels when people move around the country? Don Beyer, the Democratic congressman from Virginia, has a bill proposing that people traveling within the United States on airplanes and trains should either be vaccinated or provide proof of a negative COVID test," MSNBC host Katty Kay said.

That proposed legislation is called the "Safe Travel Act" and it "would require proof of vaccination or a negative covid test within 72 hours of travel for domestic airline and Amtrak trips." This is something international travelers coming to the US have had to undergo, but not a restriction placed on Americans for travel within the US.

"This is very common practice now in Europe," Kay explained, "I've just been traveling all over Europe, you can't get on a plane without having some kind of proof that you're negative. It seems to me crazy that a year and a half into this, you can still I can still get on a plane to Boston or California. Nobody's going to check me. Do you think that needs to change?"

"Well, that's another consideration, certainly," Fauci said. "I mean, I have been asked that question. And it actually got got some play in the press when I made the answer," he laughed.

Fauci said at the time that he would throw his support behind a plan that required proof-of-vaccination for domestic US travel. "I would support that if you want to get on a plane and travel with other people, that you should be vaccinated," Fauci said.

"I think that if, in fact, it is seriously considered, it's on the table. We're not there yet. In fact, if you look at the six-point program that the President came out with a couple of days [ago], what we were talking about with travel was doubling the fines of people who in fact, are traveling and don't get tested. And I and I believe that the idea about requiring vaccination for travel is something that is on the table for discussion. It has not been decided yet," Fauci said.