To say this would be a significant escalation of Russia's anti-western campaign is really a big understatement. According to a report in Wall Street Journal, Russia has recently been testing out plans to put explosive devices on US and UK airliners. The initial tests involved incendiary devices which started fires on planes carrying packages to Germany and the UK.

Western security officials say they believe that two incendiary devices, shipped via DHL, were part of a covert Russian operation that ultimately aimed to start fires aboard cargo or passenger aircraft flying to the U.S. and Canada, as Moscow steps up a sabotage campaign against Washington and its allies.

The devices ignited at DHL logistics hubs in July, one in Leipzig, Germany, and another in Birmingham, England. The explosions set off a multinational race to find the culprits.

Investigators determined that electric massagers had been packed with magnesium to make them flammable were sent on the flights by a company in Lithuania.

Poland’s National Prosecutor’s Office said authorities there have arrested four people in connection with the fires and charged them with participating in sabotage or terrorist operations on behalf of a foreign intelligence agency. Poland is working with other countries to find at least two more suspects.

“The group’s goal was also to test the transfer channel for such parcels, which were ultimately to be sent to the United States of America and Canada,” the prosecutor’s office said, without saying who was orchestrating the group’s efforts.

The head of Poland's prosecutor's office said that Russian spies were behind this test run. Other unnamed western intelligence officials said the GRU was responsible.

The idea that Russia might target US or UK airliners shouldn't seem far-fetched. It was only 10 years ago that their forces in Ukraine shot down Malaysia Airlines Flight 17. 

Russia has been escalating its sabotage against western targets for the past several years. Back in May the WSJ published a story about some of these efforts.

Last fall, Finnish investigators linked a Chinese-registered ship, operated by a Russian crew, to the cutting of the Balticconnector natural-gas pipeline to mainland Europe. As the investigation advanced and the ship sailed around Scandinavia back toward Russia, the Finns contacted Norwegian counterparts about their suspicions. Norwegian authorities contemplated forcing the ship into one of their harbors for inspection, but ultimately decided they lacked clear evidence. A Norwegian coast-guard ship shadowed the Newnew Polar Bear as it was passing sensitive marine infrastructure.

“Only a week or two later we would have had enough evidence to stop and search the ship, but by then it was already too late,” one Norwegian official said...

In January 2022, as Russia was positioning its forces to attack Ukraine, a Russian fishing trawler was detected traversing the icy waters above a major fiber-optic cable around the time it was cut. The cable carried data from SvalSat, one of the largest commercial satellite ground stations in the world, located on Norway’s Svalbard archipelago in the far north.

The Russian trawler crisscrossed more than 100 times over the exact spot where the cable was cut, according to satellite traffic-monitoring data, said Ronny André Jørgensen, a prosecutor from the northern city of Tromsø who investigated the incident.

CNN published a follow-up in July.

Recent high-profile arrests have revealed the ad-hoc, clumsy nature of how the Kremlin’s intelligence operations have evolved since the start of the war in Ukraine. Last year, 14 Ukrainians and two Belarusians were arrested in Poland in one case on suspicion of working for Russian intelligence. A Ukrainian, who under Polish privacy law can be identified only as Maxim L., 24, was sentenced to six years after weeks of receiving tasks from a Russian handler, Andrzej, whom he had never physically met but encountered on the Telegram messaging app in February 2023...

Last month, a suspicious fire hit a metals factory for a defense manufacturer outside Berlin, and a 26-year-old pro-Russian Ukrainian was arrested after blowing himself up with a homemade bomb near Paris Charles de Gaulle airport. A warehouse fire in East London in March led to two men being charged by London’s Metropolitan Police Service with arson and assisting a foreign intelligence service, namely Russia.

While the incidents have not all been definitively linked to Russian intelligence, they have been unified by the apparent involvement of amateurs, or petty criminality aimed at spreading fear or disruption.

We know Russia is behind these incidents and Russia knows that we know. But there's not enough evidence in most cases to make the case in court. It sounds like that's the same sort of thing Russia was going for with the incendiary devices on planes. If one went off and a plane crashed, it would be very difficult to determine what started the fire and to trace that back to anyone in particular. Even if mass casualties were involved, there's no guarantee anyone could be held responsible.