The plane suspected of carrying €8.4m of cocaine into an airfield in Abbeyshrule, Longford, on Thursday afternoon had left the same airfield the day before to fly to Dieppe, Normandy, where it is believed the consignment was loaded onto the aircraft.
The light aircraft had been engaged in internal flights in Ireland in recent weeks, but had also made trips to Scotland and Belgium in recent months. It flew to the same airport in France in mid-July.
This is believed to be one of the first times such a method was used to bring drugs into Ireland, according to gardaí.
Two men are being questioned in connection with the discovery of €8.4m of the drug, which garda sources say is one of the biggest seizures of the drug made on land in Ireland by gardaí. It is the biggest one so far this year.
Gardaí say they are trying to establish the links between Ireland and continental Europe in the drug-trafficking operation, including whether the aircraft had been used for similar purposes previously.
Any possible connection between this operation and an aircraft which was seized in Waterford in early March will also be probed, although sources do not see any obvious link at present.
The investigation involved searches in Westmeath, Kildare, Waterford City, and Longford, under Operation Tara, targeting drug activity.
Around 120kgs of cocaine was seized in Co Westmeath after gardaí intercepted two vehicles on Thursday shortly after 6pm. Personnel attached to the Garda National Drugs and Organised Crime Bureau, supported by other national units, intercepted the vehicles at two locations in the Lough Owel area.
The light plane was seized at a commercial airfield in Abbeyshrule, Longford, as part of the probe.
The men who are in custody are aged 54 and 40 years, respectively, and are being held in Ashbourne Garda Station.
They were arrested on suspicion of drug trafficking, contrary to Section 15 of the Misuse of Drugs Act 1977, and are being questioned under Section 2 of the Criminal Justice (Drug Trafficking) Act 1996.
A Garda source said: “It is definitely the biggest seizure of the year, and probably one of the biggest ones we have ever had on land — as opposed to those coming in through containers or the ports.”
Gardaí say light aircraft are not subject to the same requirements of flight plans as aircraft flying into larger airports.
The source said: “There is a bit of work to be done around flight routes and flight plans.”
However, gardaí will be analysing “several communication devices” seized as part of the operation, including mobile phones, to progress their investigation.
Following the operation, Assistant Commissioner Justin Kelly, the head of Organised and Serious Crime, said: "This operation has prevented a considerable quantity of dangerous drugs from making it onto our streets and causing significant harm to our communities."
"An Garda Síochána is committed, under Operation Tara, to disrupting and dismantling the organised criminal networks who profit from drug trafficking and impact so negatively on our society."
The seizure was described by former Assistant Commissioner Micheal O’ Sullivan as “a huge blow” to the transnational gang.
A former director of MAOC (Maritime Analysis and Operations Centre), he said: “€8.4m worth of coke, or 120kg, is a huge amount, and all credit certainly goes to the drugs and organised crime bureau who were behind this.
He told RTÉ’s: “A lot of people are going to lose money, it will certainly disrupt if not dismantle sections of an organised crime group.”
Meanwhile, yesterday, also as part of Operation Tara, gardaí in Bray seized drugs valued at €90,500.
Gardaí became suspicious of a man who ran from a car he was in, and after they stopped the 22-year-old and searched the car, cannabis and cocaine were discovered.