Rep. Don Beyer (D-Va.) introduced a bill on Thursday to require all domestic travelers to show proof of vaccination or a negative coronavirus test at airports or for Amtrak trips, seeking to revive largely stagnant discussions among federal officials about more restrictive pandemic travel requirements.

The bill, the Safe Travel Act, would also require all Amtrak, airport and air carrier employees or contractors to be vaccinated or submit to weekly testing. Unvaccinated travelers would have to present a negative test within 72 hours before travel.

Beyer, who chairs the House Science, Space, and Technology subcommittee on space and aeronautics, said in a statement that the proposal would “help make people comfortable traveling again by putting basic requirements in place that prevent the spread of Covid.”

“Requiring airport and Amtrak travelers and employees to provide a proof of COVID vaccine or negative test is just common sense,” Beyer said. “These are easy steps we can take to make travel safer, as companies like United have already demonstrated with responsible policy changes.”

Beyer’s proposal comes as the spread of the delta variant has upended progress the country has made toward suppressing the coronavirus, forcing many to reconsider travel plans, and as more governmental and private entities introduce vaccine mandates for employees — including airlines.

United and Hawaiian airlines have instituted vaccine mandates, while Frontier and Delta require unvaccinated employees to submit to weekly testing, and Delta also requires they pay a $200 monthly insurance surcharge. Amtrak also already mandates vaccination for employees, unless they submit to weekly testing. Kimberly Woods, a spokeswoman for the company, said Amtrak declined to comment on Beyer’s legislation.

But legislation to expand vaccination or testing requirements for all domestic travelers would test the limits of how far the Biden administration is willing to go — and it has already indicated earlier this year that it would not go that far, complicating the prospects for Beyer’s bill.

President Biden announced sweeping new vaccine mandates on Thursday, including for the entire federal workforce and all federal contractors; for employees at health facilities receiving Medicaid or Medicare funding; and, through a forthcoming rule from the Department of Labor, for companies with more than 100 employees, affecting tens of millions of Americans.

The president’s “Path out of the Pandemic” plan did not include any additional restrictions for domestic travelers, however, except for doubling fines at airports and on other modes of public transportation for refusal to wear a mask.

A proposal to expand vaccination or testing requirements for all domestic travelers would likely be met with pushback from the airline industry, even though proof of a negative coronavirus test is already required for international travelers, regardless of vaccination status.

At the time that rule was put into place, federal health officials also raised the possibility they might extend the requirement to those flying within the United States.

But the idea drew immediate opposition from airlines who argued that it would be impossible to implement and would further hamper the industry’s hoped-for recovery.

The White House did not respond to questions about whether Biden would support the proposal. In February, the Biden administration said it had no plans to mandate testing for domestic travelers.

The vaccine and testing requirements also would apply to airport workers.

Rob Yingling, a spokesman for the Metropolitan Washington Airports Authority, which manages Reagan National and Washington Dulles International airports, said while employees are required to wear masks while on the job, there is no requirement that they be vaccinated. Yingling said MWAA does not have statistics on the percentage of workers who have received the shots.

Jonathan Dean, a spokesman for Baltimore Washington International Airport, said that “we continue to strongly encourage airport employees to be vaccinated” and that the airport had a new health center offering coronavirus testing and vaccinations for passengers and employees.

Beyer’s proposal likely faces an uphill climb. More modest proposals — such as a pilot program requiring the Transportation Security Administration to screen all travelers for fevers with a temperature check — have not made progress in Congress, even with bipartisan support.

Rep. Ritchie Torres (D-N.Y.) has put forth legislation to require all travelers at airports to be fully vaccinated, while a number of Republicans have introduced legislation to prohibit “vaccine passports” or proof of negative coronavirus tests at airports. None of those proposals have made progress.