Though flights were normal Sunday at Minneapolis-St. Paul International Airport, travelers need to be on alert this week for flight delays or cancellations, as a new furlough system for air traffic controllers kicks in under federal spending cuts required by the sequester.

Beginning Sunday and continuing until Sept. 30, controllers must take one day of unpaid leave per two-week pay period.

Federal Aviation Administration officials said last week that the cuts were unavoidable, and warned that the new work schedules could slow the pace of airline takeoffs and landings at the nation's busiest airports. On Sunday evening some delays were reported in and around New York City.

Mark Duell at the flight tracking website FlightAware said that John F. Kennedy Airport averaged 70-minute delays for inbound flights, but no detectable departure delays. LaGuardia averaged 74-minute delays for inbound flights, and departure delays of 37 minutes.

Metropolitan Airports Commission spokesman Patrick Hogan reported nothing unusual as the furloughs began, but said there will probably be delays in the coming days.

"Uncertainty is going to remain with us until funding is restored," Hogan said. "Given the volume of flights we have, there could be an impact regardless of what day of the week it is."

Hogan said local air traffic managers expect to keep up with airline traffic. "But if someone calls in sick or goes on vacation, they could become short-staffed because they won't have as much flexibility," he said.

It's always a good idea for consumers to check with their airlines before going to the airport, he added, especially now that furloughs have begun.

Hogan said that the moderate delays at New York airports weren't having any significant impact in Minnesota Sunday evening.

The FAA released a list of 13 of the nation's busiest airports where flights could be delayed, including Kennedy International and La Guardia in New York, O'Hare in Chicago, Los Angeles International, Newark Liberty International, and Atlanta's main airport.

"Fortunately we're not on that list," Hogan said. "But we have a lot of flights to Chicago and Atlanta and other airports that might have slowdowns."

Schedules at Minneapolis-St. Paul International Airport could be disrupted if flights are backed up or canceled at other airports, he said, much the way severe weather at one airport can create cascading problems on schedules and connecting flights across the nation.

Two airline associations and a pilots' union filed a lawsuit in federal court late last week to halt the furloughs, but a hearing has not been held.