(NewsNation) — Federal lawmakers have until midnight to pass a budget, or else the government will shut down, impacting millions of employees and consumers ahead of the holiday. Without a funding plan, the shutdown would begin at 12:01 a.m. Dec. 21 and last until Congress passes a spending bill. Here are the government services and agencies that would be affected if the government shuts down. What does a government shutdown impact? Federal employees, including military members, would not be paid. Non-essential agencies would stop service, while essential workers, such as police officers and air traffic controllers, would still report for duty. Citizens who don't work for the government may be impacted as well if certain agencies are closed or understaffed. Johnson says plan C reached to avert shutdown, vote expected Air Travel: The Transportation Security Administration is considered essential, so employees would be working without pay. Still, delays and interruptions could happen, and any extended shutdown "could mean longer wait times," the TSA administrator warned Thursday. Social Security: Payments for current recipients would continue because Social Security is deemed essential, but services for new claims could be delayed due to furloughed staff. Medicare and Medicaid: Current recipients would continue to receive benefits, but new applicants could see delays. Mail Service: The United States Postal Service would continue operations and remain open. Student Loans: Student loan services would continue to process payments, and payments will still be due. Speaking with an agent or getting help may come with delays, however. Government Employee Pay: Furloughed federal employees would receive back pay when a shut down ends, but government contractors will not. Passport Services: The processing of passport applications may be slowed or halted. FEMA Cleanup and Protection: The agency will still respond to emergencies in the event of a disaster, but long-term projects would be delayed. National Parks and Museums: Many national parks and federally funded museums would likely close or have limited operating hours. Food Assistance Programs: People who receive benefits under the Supplemental Nutrition Assistance Program (SNAP) would continue to receive payments, but new enrollment or renewals could face delays.