The suspects, aged 30 and 43, were charged Friday for 'association with terrorist criminals' over the March 18 incident, the latest in France which remains on a state of emergency after a series of deadly attacks.
Both men are being held in custody, the source said. The younger one was also charged with arms possession related to a terror plot.
They are both from the Paris area and lived close to the assailant, Ziyed Ben Belgacem, but neither of them had links with any radical movements, according to a preliminary investigation.
The 30-year-old detained Friday is suspected of having given Ben Belgacem a revolver a few days before the attack, while the older suspect was present when it was handed over.
The younger man admitted once in custody having been in possession of the gun and kept it at his home, before Ben Belgacem came to get it, a source close to the investigation said.
Questioning of both of them revealed no further details about Ben Belgacem's plans, said the source.
The Orly attack, which came a month and a half after a similar assault at the world-famous Louvre museum in Paris, bears the hallmarks of the ISIS, but has not been claimed by the terror group.
Ben Belgacem was under the influence of drugs and alcohol when he attacked the capital's second busiest airport, according to judicial sources.
The 39-year-old, born in France to Tunisian parents, grabbed a soldier on patrol at Orly's southern terminal and put a gun to her head and seized her rifle.
His father insisted his son - who had spent time in prison for armed robbery and drug-dealing was not an terrorist.
He had, however, been investigated in 2015 over suspicions he had been radicalised while serving jail time, but his name did not feature on the list of those thought to pose a high risk.
The attack at Orly came with France still on high alert following a wave of terrorist attacks that have claimed more than 230 lives in two years.
The violence has made security a key issue in France's two-round presidential election on April 23 and May 7.
Soldiers guarding key sites have been targeted in four attacks in the past two years but escaped with only minor injuries.
In mid-February, a machete-wielding Egyptian man attacked a soldier outside Paris's Louvre museum, injuring him slightly, before being shot and wounded.