A Florida man who flew a small gyrocopter through protected Washington airspace before landing outside the U.S. Capitol last spring was seconds away from colliding with a Delta flight that had taken off from Reagan National Airport, prosecutors said.

In a court filing Friday, prosecutors said Douglas Hughes flew his one-person aircraft almost directly into the oncoming flight path of the 150-person Airbus turbojet last April. Hughes came within 1,400 yards of Delta Flight 1639, while safety rules require aircraft to remain separated by more than 3,000 yards.

“If the gyrocopter had drifted slightly west, or the airline had taken a slightly more easterly path, a collision could have occurred,” prosecutors said. Such a collision could have been “catastrophic,” they added.

Hughes, who agreed to a plea deal in November, is set to be sentenced April 13. Prosecutors are asking for 10 months in prison, arguing the former mail carrier from Ruskin, Florida, put countless lives at risk.

Hughes rejected the prosecution court filing in an email Saturday to The Associated Press, saying he knew where the commercial air traffic was and “I didn’t go there.”

“The ‘story’ that I almost collided with a passenger jet is a fabrication,” wrote Hughes, adding that “the prosecution is either intentionally deceptive or grossly negligent in their presentation of the evidence.”

He added in his email, “At NO time, was I a threat to commercial traffic.”

Hughes’ attorneys say they don’t think he should have to serve any more time behind bars, noting that no one was injured and no property was damaged. Hughes spent one night in jail after the stunt, served five weeks in home confinement and had this travel privileges restricted for nearly a year.

Mark Goldstone, an attorney for Hughes, said they will look into the government’s claim about the Delta flight. But he questioned why prosecutors are now saying Hughes flew closer to the plane than they previously reported.

“It seems suspicious that on the eve of sentencing, all of a sudden his flight was about to blow up a commercial airliner,” Goldstone said Saturday.

Hughes pleaded guilty in November to a felony of operating a gyrocopter without a license. The charge carries a potential three years in prison, but prosecutors agreed not to ask for more than 10 months in prison as part of a plea deal.

Hughes has said he was trying to send a political message about the need for stronger campaign finance restrictions by flying the aircraft to Washington after taking off from Gettysburg, Pennsylvania. He told investigators during an interview after he was arrested that the only way he potentially put lives in danger was if “authorities overreacted” and tried to shoot him down.

Hughes’ attorneys argue that while Hughes broke the law, prosecutors should not respond in a way that discourages Americans from expressing their grievances about their government.

“Suppressing or even discouraging political dissidence is a very dangerous and undemocratic prospect,” his attorneys wrote.

Prosecutors said Capitol Police officers were in position to shoot Hughes when he landed and that one of the officers had him in his gunsight with a round in the chamber. They noted that Hughes’ flight took him less than a mile from Vice President Joe Biden’s home, about 175 feet from the Washington Monument and close to other landmarks.

They say prison time is necessary to deter such action in the future.

“Whether the next airspace violator is an unpopular religious extremist who wants to impact US foreign policy or a popular advocate on any issue of domestic policy, the deterrent message must be clear: If you violate the airspace of our nation’s capital — regardless of your message — you will be punished because of the substantial risks to safety and national security,” prosecutors wrote.

Hughes’ attorneys say he has pledged that he will comply with the law from now on as he continues his push for political change. Hughes has said he plans to challenge South Florida Rep. Debbie Wasserman Schultz for her 23rd Congressional District seat.