The push for coronavirus vaccine and testing mandates in the sky has another proponent.

Sen. Dianne Feinstein (D-Calif.) introduced a bill on Wednesday that would require vaccination, a negative coronavirus test or recovery from covid-19 to take a domestic flight.

This latest proposed legislation follows a bill introduced earlier this month by Rep. Don Beyer (D-Va.) that would require proof that air or Amtrak travelers have been vaccinated or tested negative.

“Ensuring that air travelers protect themselves and their destination communities from this disease is critical to prevent the next surge, particularly if we confront new, more virulent variants of covid-19,” Feinstein said in a statement.

She pointed out that air travelers coming to the United States from abroad already have to provide a negative test, even if they are traveling from countries with lower rates of transmission than many parts of the country. Starting in early November, restrictions on travel from 33 countries will fall as the United States moves to a new vaccine requirement for foreign visitors. Those visitors will also need to show proof of a negative test.

“It only makes sense that we also ensure the millions of airline passengers that crisscross our country aren’t contributing to further transmission, especially as young children remain ineligible to be vaccinated,” Feinstein said in the statement.

This month, President Biden’s chief medical adviser, Anthony S. Fauci, said he would support a vaccine mandate for air travel. He told The Washington Post that the possibility was “on the table.”

Airline leaders have said such a rule would be “logistically impractical” and “incredibly cumbersome.”