Washington (CNN) -- Upcoming forced government spending cuts will heavily impact the Federal Aviation Administration, triggering flight delays nationwide and control-tower closures at some small airports as soon as April, Transportation Secretary Ray LaHood said Friday.
"Travelers should expect delays," LaHood told reporters in calling for fellow Republicans to work toward compromise to avert the worst impacts of $85 billion in across-the-board cuts set to take effect March 1.
The full impact won't be felt until April as furloughs and other staffing reductions of air traffic controllers come into effect, said LaHood, who has announced his intention to step down from President Barack Obama's Cabinet.
"Flights to major cities like New York, Chicago, San Francisco and others could experience delays of up to 90 minutes during peak hours because we have fewer controllers on staff," LaHood said. "Delays in these major airports will ripple across the country."
In addition, control towers at smaller airports such as Boca Raton, Florida, and Joplin, Missouri, would be closed, he said.
Asked why he was brought to the White House briefing room to address reporters, he said: "I would describe my presence here with one word -- Republican."
"They're hoping that maybe I can influence members of my own party" to compromise with Obama and Democrats on an alternative to the mandatory spending cuts agreed to in a 2011 deal to increase the federal borrowing limit, LaHood said.
LaHood is a former member of the House of Representatives from Illinois.
In a letter to airline associations, the Defense Department and other "aviation colleagues" released on Friday, LaHood said plans under consideration to absorb the mandatory spending cuts included furloughs for most FAA workers, eliminating midnight shifts in 60 control towers and shutting down more than 100 towers at smaller airports.
The FAA operates towers at more than 400 airports nationwide.
The Homeland Security Department has separately warned of longer security lines at airports if budget cuts take effect, another potential headache for air travelers.
CNN's Tom Cohen contributed to this report.