Janet Napolitano, secretary of Homeland Secretary, says furloughs at the Transportation Security Administration and Customs and Border Protection could lengthen security lines at the busiest airports. Lines at TSA security checkpoints could get an hour longer, according to House Democrats. And Napolitano says two-hour Customs lines could grow to four hours.
Federal workers get 30-days notice of furloughs, so none of these problems are expected to begin until April. Congress and President Obama could still reach a compromise that spares the FAA and TSA from the cuts.
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But based on daily meetings with federal officials, Freni is preparing the same as for a major storm.
If planes get stuck on Logan's tarmac from delays, Freni says he can get passengers back inside the terminal. If too many planes arrive at full gates, he can move passengers through another terminal to reunite them with luggage and get them home. (Read more: Are Rules Limiting Tarmac Delays Working?)
Inside, volunteers will answer questions for people waiting in lines. The airport works with concessionaires to stay open longer if travelers get stuck. The airport has 700 cots.
"We'll make people as comfortable as possible, providing water and blankets and food – if it gets to that," Freni says. "I liken it to a big snowstorm throughout the whole system."
In Atlanta, airport general manager Louis Miller says air-traffic control furloughs could force him to close one of five runways at the world's busiest airport.
"That would cause arrival delays and departure delays during the busiest parts of the day," Miller says. "It's a ripple effect."
The typical 10-minute wait at TSA checkpoints could stretch to 30 or 40 minutes during the busiest periods, Miller says. Average Customs waits of 16 minutes for Americans and 19 minutes for foreigners could also grow, he says.
"To us, that's just unacceptable," Miller says of longer TSA lines.
As furloughs approach, Miller says, the airport will urge travelers to arrive earlier for security and to have patience with airline delays. Customer-service workers will be at security lines to answer questions and perhaps direct travelers to another of the airport's four checkpoints.
"People really need that — they need to know what's happening," Miller says.
John Albrecht, spokesman Oakland International Airport, says staffers are taking a fresh look at contingency plans in case there are any disruptions. In working with federal agencies, he says, the goal remains the same for safe, secure, on-time travel.
Victoria Lupica, spokeswoman for Philadelphia International Airport, says staffers are working with the FAA, TSA and Customs and Border Protection about possible changes in operations.
"While the safety of air travelers will never be compromised, we will continue as always to work collaboratively with our federal partners to keep the impacts on our travelers at a minimum," Lupica says.
At smaller airports, closing towers isn't enough to shut down traffic because planes can still take off and land on their own. But FAA Administrator Michael Huerta says the lack of controllers makes airports less efficient, especially in bad weather, as planes wait for each other to alternate landings and takeoffs.
Airports that could lose midnight shifts include some popular destinations, such as Chicago's Midway and Reno, Nev.
Southwest Airlines, a major carrier at both those locations, is working with the airports and federal agencies to protect travelers, says Chris Mainz, an airline spokesman.
"We do not expect any immediate delays to our operation, but we are closely monitoring the situation for potential customer disruptions," Mainz says. "As always, we encourage customers to check Southwest.com or AirTran.com for specific flight updates."