(NBC NEWS) -- With furloughs for the nation's air traffic controllers set to begin on Sunday, fliers may need to rethink their travel plans -- and their traditional weekend rallying cry.
"What happened to TGIF?" asked Faye Malarkey Black, senior vice president - legislative affairs for the Regional Airlines Association (RAA), during a press conference on Friday. "I guess now we can just say, Thank God it's not Sunday yet."
In fact, come Sunday, fliers may get a firsthand look at the impacts of the automatic budget cuts put in place by Congress last year. As part of the sequester, the Federal Aviation Administration (FAA) expects to furlough many of its nearly 15,000 air traffic controllers (ATC) for one day per two-week pay period.
The result is expected to reduce control-tower staffing at any time by 10 percent, a move that Nick Calio, CEO of Airlines for America (A4A), said could result in as many as 6,700 flight delays per day.
"During the worst day in 2012, there were almost 3,000 delays, mostly due to severe weather," Calio told reporters. "Assuming good weather, FAA predicts more than twice as many delays due to the sequester."
Not surprisingly, perhaps, the most likely delays and cancellations are expected to occur at the nation's busiest airports, many of which already operate at or above capacity during peak periods. According to FAA, worst-case scenarios include delays of more than 3 hours at Atlanta-Hartsfield, more than 2 hours at Chicago-O'Hare and 50-80 minutes at New York's airports.
But the nature of the air traffic system means any delays could quickly spread across the country due to ground stops, in which planes are kept on the ground at originating airports because there are no gates at their destinations.
"It's going to start to snowball on Sunday, which is a slow flight day," said Lee Moak, president of Air Line Pilots Association, International (ALPA). "By Sunday afternoon, it's picking up and by Monday, we're into the full flight schedule. If those delays take effect, it will not be very long before the system comes to a grinding halt."
The key word, of course, is "if" as specific staffing cuts haven't been announced.
"With the sequester, FAA has some leeway," said Rick Seaney, CEO of FareCompare.com. "If they yank (controllers) out of 6 or 7 choke-points, they could cause all sorts of heartburn; if they do it in places where it doesn't matter as much, it could have minimal impact."
With FAA withholding more detailed information, A4A, ALPA and RAA filed suit on Friday, seeking to postpone the furloughs for 30 days, although Calio didn't expect a decision to be delivered before Sunday.
In the meantime, airports are ramping up contingency plans to accommodate passengers facing potential delays, says Chris Oswald, vice president, safety and regulatory affairs for Airports Council International - North America (ACI-NA), an airport industry trade group.
"That includes things like working with the airlines to get passengers offloaded from aircraft that won't be departing, ensuring that concessions will be open in the evenings and being available to assist passengers affected by cancelations," he told NBC News.
Travelers should also take a proactive approach, says Seaney, suggesting that they sign up for flight alerts, monitor FlightStats.com for real-time air-traffic reports and keep an eye on what's trending on social media before they head to the airport.
"It's all about getting good, quality information," he told NBC News, "and sometimes you can get better information from Twitter than you can from a gate agent."
As for those who can't get advance intel and find themselves stuck at the airport for hours on end, Oswald of ACI-NA offers the age-old advice to hope for the best but prepare for the worst by bringing a book, making sure your batteries are charged and making the most of your downtime:
"I know, for me as a business traveler, that if there's something I can do to be productive at the airport, the pain's a whole heck of a lot less.