Antoine Quilichini, 49, known as "Tony the Butcher", died on the spot from a bullet to the head and Jean-Luc Codaccioni, 54, who was on leave from prison, was flown by helicopter to hospital after being shot in a carpark at the airport at Bastia on the north of the island.
A third man, who was 35-years-old, was lightly wounded in the buttock as he tried to flee the scene.
Officials say they believe he was not targeted by the attackers, two men who fled in a black Volkswagen, according to police.
A murder inquiry has been opened but Bastia public prosecutor Caroline Tharot has handed the case over to the organised crime unit in Marseille.
Quilichini was convicted in 2016 of conspiring to murder Jean-Claude Colonna, the cousin of south Corsican mafia boss Jean-Baptiste Jérôme Colonna, known as "Jean-Jé".
Codaccioni, who was at the airpot after being allowed to leave the island for personal business, was still serving time for his role in the same killing.
Quilichini is an associate of Jean-Luc Germani, the brother-in-law of Richard Casanova, a member of a notorious gang in the north of the island who was murdered in 2008.
He was jailed for two and a half years in 2013 for his role in an attempt to take control of a Paris casino.
Corsica has a long history of organised crime, including the heroin smuggling networks that inspired William Friedkin's 1972 film The French Connection.
Corsican nationalists waged a bombing campaign for nearly four decades before laying down their arms in 2014.
Pro-autonomy parties won an unprecedentedly high vote in last Sunday's first round of local assembly elections and are expected to take control of it in the second round next Sunday.