Douglas Hughes, the Florida letter carrier who violated national airspace by landing his gyrocopter on Capitol Hill last month, could face 9.5 years in prison after he was indicted Wednesday by a federal grand jury.

Hughes, 61, of Ruskin, Florida, was charged in Washington, D.C., with flying without proper certification and violating aircraft registration requirements, both of them felonies, and misdemeanor counts of violating national defense airspace and operating a vehicle falsely labeled as a postal carrier.

His next court appearance was scheduled for May 21 in U.S. District Court.

RELATED: Gyrocopter landing raises serious security questions

In addition to the possible prison term, the government wants to keep Hughes’ gyrocopter, which he flew from Gettysburg, Pennsylvania, to Washington on April 15 and landed on the West Lawn of the U.S. Capitol.

Hughes has said the airborne breach was to protest the influence of big money in politics by deliberately breaking the law to deliver 535 letters — one for each voting member of Congress.

More than anything else, however, Hughes sparked a debate over holes in national security, not political spending.

Still, “I think it was worth it,” he told WTOC-TV of Savannah, Georgia, where he stopped Tuesday on his way to Washington for Wednesday’s proceedings.

Prosecutors said Hughes managed to pass through three no-fly zones even though he’d given plenty of notice he was on his way. He’d written about what he called the Freedom Flight as early as September 2013 — the Secret Service even visited him at his home the next month. And he sent out an email blast to Florida media organizations before he flew into Washington on April 15.

Hughes remains free on his own recognizance, but he is barred from returning to Washington except for court appearances and meetings with his attorney. He’s also barred from operating any aircraft.