The Florida postal worker who landed a gyrocopter at the U.S. Capitol to protest campaign finance laws vowed to continue speaking out against the influence of money in politics after pleading guilty Friday to a felony charge of flying without a license.

Douglas Hughes, 62, of Ruskin, Fla., admitted to operating without an airman’s certificate, the lead count of a May indictment charging him with six felony and misdemeanor offenses for flying his low-power gyrocopter from Gettysburg, Pa., to the District on April 15.

The offense is punishable by up to three years in prison. The two sides in the plea deal agreed that no sentencing guideline applies, leaving U.S. District Judge Colleen Kollar-Kotelly free to go lower.

Hughes also agreed to forfeit his ultralight craft, which was modified with bins to hold letters he had planned to send to members of Congress, as well as a 10-gallon gas tank.

The judge set sentencing for April 13.

Hughes said he will ask for probation, arguing that his flight caused no injury or damage. Prosecutors said they would seek a 10-month term. He faced up to 91 / 2 years in prison if convicted of the original charges.

Hughes and protest organizers supporting him said he hopes in the days before he is sentenced to join a 10-day march on Washington from Philadelphia — from the Liberty Bell to the U.S. Capitol — near the anniversary of his flight.

“We’re going to turn the country around on money in politics” and “restoring representative democracy,” Hughes told reporters outside the E. Barrett Prettyman Federal Courthouse in Washington. “This is the best way for me to return to the battle.”

March organizer Kai Newkirk said his group, 99Rise, was halfway to its goal of 1,000 demonstrators pledging to risk arrest in a sit-in at the U.S. Capitol in what he called a “Democracy Spring” march.

“Doug’s courageous act . . . lifted this issue up and we have to do that on another scale,” said Newkirk, whose group has disrupted Supreme Court arguments three times since early 2014 to protest the court’s 2010 decision loosening election financing limits in Citizens United v. Federal Election Commission.

Kollar-Kotelly warned Hughes’s attorneys: “He does this at his own risk.”

The judge did not say whether she would allow him to attend the rally by altering terms of his conditional release, which limit him to the confines of Hillsborough County, Fla. She asked for further briefings.

The contraption that landed on the Capitol’s West Lawn

In court, Assistant U.S. Attorney Tejpal S. Chawla opposed allowing Hughes to travel for the rally, saying that Hughes’s plan showed his mind-set had not changed since his offense triggered a Capitol lockdown.

“It creates a situation where this court could be turned into a circus,” Chawla said. “We want legitimate protest that is not in violation of our laws.”

Hughes’s attorney, Mark L. Goldstone, assured the court that Hughes “has no intention of getting arrested.” Newkirk, speaking later to reporters, also ruled out any court disruptions.

The judge posed another question: If she allowed Hughes to travel for the march, how was he planning to get to Philadelphia?

“To fly . . . by commercial aircraft,” said Hughes’s other attorney, Assistant Federal Public Defender Tony W. Miles, eliciting laughter from the judge and throughout the courtroom.

Piloting what was described as a “flying lawn chair” powered by a small motor-driven propeller, Hughes flew through restricted airspace, over the National Mall and onto the southwest lawn of the Capitol.

The Federal Aviation Administration does not require pilots to be licensed to fly ultralight vehicles less than 254 pounds, but with Hughes’s modifications, his craft exceeded that weight.

“Douglas Hughes put himself and countless others in danger,” U.S. Attorney Channing D. Phillips of the District said in a statement. “This prosecution will hopefully deter others from violating the highly restricted airspace surrounding Washington, D.C.”

Hughes’s other charges included operating without an aircraft registration, three misdemeanor counts of violating national defense airspace and one misdemeanor count of operating a vehicle falsely labeled as a postal carrier.