By David Shepardson and Tracy Rucinski

WASHINGTON/CHICAGO (Reuters) – U.S. airlines would receive $17 billion for four months of payroll support under a new $908 billion bipartisan Senate COVID-19 relief proposal, staffers for two U.S. Senators said on Tuesday.

A bipartisan group of lawmakers announced a package of $45 billion in transportation assistance, and the offices of Senators Mitt Romney and Mark Warner said the plan includes $15 billion for transit systems, $4 billion for airports, $8 billion for private buses and $1 billion for passenger railroad Amtrak.

The $45 billion in transportation assistance is designed to provide assistance for four months. Congress and President-elect Joe Biden can decide next year if more funds should be approved beyond March, Senator Joe Manchin said.

The White House has not yet said it supports the plan, and neither have Congressional leaders. A separate Senate Republican leadership relief plan summary sent to lawmakers later on Tuesday had no reference to additional transportation assistance.

In October, American Airlines (NASDAQ:) and United Airlines furloughed more than 32,000 workers after a prior $25 billion payroll assistance program expired.

For months, airlines had sought another $25 billion bailout to keep workers on the payroll for another six months.

Romney said lawmakers spoke to Treasury Secretary Steven Mnuchin seeking input on “what was the right number for airlines.”

U.S. passenger airline traffic remains down by more than 60% and planes are flying on average just half full. Airlines have lost more than $36 billion in 2020.

Airlines for America President Nick Calio praised the proposal that includes “provisions intended to help airlines make payroll and protect the jobs of our industry’s hardworking employees.”

Association of Flight Attendants-CWA International President Sara Nelson said the union was “working with lawmakers to ensure this emergency relief is enacted immediately.”

Transit agencies have urged Congress to approve $32 billion in additional assistance, while Amtrak sought nearly $3 billion and to prevent new service and job cuts. Airports sought another $10 billion after receiving $10 billion in April.

On Monday, the Washington DC-area subway system said it planned to end weekend train service and cut one-third of bus routes in mid-2021 without new government help. Last month, New York said subway and bus services could be cut 40% without new help.

Private U.S. bus companies, school bus and domestic passenger vessel industries have sought $10 billion in government assistance after massive job losses and made a new urgent appeal on Monday to Congress.