Transportation Secretary Ray LaHood | Mark Wilson / Getty Images North America

Transportation has become the latest flash point in the battle over sequestration, with Democrats and the White House warning travelers they could be in for long lines and flight delays as a result of the automatic cuts, set to go into effect on Friday.

“We can fix this,” said Virginia Sen. Tim Kaine (D) this week during a press conference at Reagan National Airport. “It doesn’t have to be this way. We need to embrace a reasonable path of deficit reduction.”

But Republican leaders on transportation issues say the claims of flight delays of up to 90 minutes during peak times at major airports and long security lines are exaggerated.

“Before jumping to the conclusion that furloughs must be implemented, the Administration and the agency need to sharpen their pencils and consider all the options,” said Sen. John Thune (S.D.) and Reps. Bill Shuster (Pa.) and Frank A. LoBiondo (N.J.), about plans to furlough employees at the Federal Aviation Administration.

To help make sense of it all, here is a quick primer that outlines the impact some say sequestration could have on the traveling public.

LaHood said that to meet its obligation to slice $600 million from its budget, the FAA will have to furlough the vast majority of its 47,000 employees, which means fewer air traffic controllers managing air traffic in the system. As a result, LaHood said, control towers at about 100 mostly small and mid-size airports will be shuttered. Those include two airports in Virginia and five in Maryland. While airports such as Manassas Regional Airport can continue operating without a tower, officials there worry about the effect of the furloughs on safety.  In addition, midnight shifts at about 60 airports would be cut.

The FAA’s 47,000 employees would probably be furloughed one day in each two-week pay period until the end of the fiscal year in September — roughly 11 days. Flights to major cities such as New York, Chicago and San Francisco could experience delays of up to 90 minutes during peak hours, LaHood said.

Travelers’ journeys could also be complicated by cuts at the Transportation Security Administration and U.S. Customs and Border Protection, according to Secretary Janet Napolitano. She said that furloughs could mean limits on accepting new international flights and could mean as much as a 50 percent increase in wait times to clear customs at  some of the busiest airports. At Newark, LAX and O’Hare, peak wait times, which are now about two hours, could grow to four or more. Limits on overtime and a hiring freeze at TSA could also mean long waits at airport security.  In all,  50,000 officers could be furloughed for up to seven days, Napolitano said.

How soon travelers will run into problems remains to be seen — and depends on whose version of the sequester you believe.

Rep. Jim Moran (D-Va.) said that it may take several weeks before the impact is felt. But he worried that the headlines could cause people to rethink their travel plans, which would be bad news for the travel industry.

Napolitano said that because the cuts hit three agencies crucial to the flying public, they represent a “perfect storm” in terms of the ability of travelers to move around the country. And once they hit: “It will be like a rolling ball. It will keep growing.”

Republicans Shuster and Thune, however, say want to see the data on which the administration is basing its conclusions.