Earlier in June, world leaders met at the G7 summit in Charlevoix, Quebec, at a riverside resort that looked like a fortress. It was guarded like one, too.

The Royal Canadian Mounted Police (RCMP) put together a special unit to provide security for the event and a heavy riot police presence discouraged protests, activists said. The extensive preparation made some sense; among other complicating factors, such as planned protests and the perceived threat of terrorism, the summit was US President Donald Trump’s first visit to Canada.

To get a sense of the scope of the security deployed for the event, and inspired by a Quartz piece that looked at private flights in Davos in 2016, I brought an antenna to Charlevoix and tracked the planes and helicopters that flew over the region in the lead-up to and during the two-day summit.

Glued to a window with a suction cup, the antenna captured nearly three million rows of data between 4 PM June 7 and 7 PM on June 9. The antenna collected data sent from the aircraft’s ADS-B transponders, devices that allow aircraft and air traffic controllers to know each other’s location.

Image: Author

Aircraft can continuously broadcast a range of information, including exact location, altitude, and a unique identification key called an ICAO 24-bit address. That code is necessary to trace the aircraft back to its owner. In the case of a commercial or RCMP aircraft, that means converting it into a registration number and searching the Canadian Civil Aircraft Registry. To look for military planes, I searched some of the many online databases maintained by hobbyists around the world.

Capturing this information is relatively cheap. I purchased the antenna that stayed in my hotel room for $26.95 USD on Amazon.com. I also had another antenna hooked up to a Raspberry Pi and a mobile phone battery so that I could harvest data closer to the summit.

Most of the 1,069 flights I identified during the summit were commercial, but I found 11 aircraft registered to a Canadian security or military agency flying close to the G7. I spotted Canadian Air Force Chinook helicopters, giant C-130 Hercules planes, more nimble Pilatus aircraft piloted by the RCMP, a military Bombardier jet, and a helicopter flown by the coast guard.

Not every plane or helicopter is equipped with ADS-B, and military aircraft rarely broadcast their location. For example, while I was able to see with my own eyes Donald Trump’s Marine One helicopter, the aircraft and its escort were nowhere to be found in my data.

Data: Author. Graphics: Marvin Lau

It’s difficult to say how the aircraft I saw were used, but most of them were likely ferrying equipment or personnel, according to Richard Aboulafia, vice president of analysis at Teal Group, a commercial and military aviation consulting firm.

“Anything can be ‘missionized,’” Aboulafia told me over phone. “Anything can be equipped with sensors and surveillance systems, but most likely the [Chinooks] were used for transport—they’re not great for endurance. What you want is something that is really capable of loitering for a long time.”

Ottawa reportedly planned to spend more than $2.2 million($1,657 million USD) to fly 3,000 RCMP officers to Quebec for the summit, so it is likely these aircraft took part in these efforts.

But the smaller planes flown by the RCMP could have been used for surveillance, Aboulafia said. “Those are interesting because a lot of people use those for sensors. Probably more likely they were used for surveillance and sensors,” he told me.

One of these smaller RCMP planes, an aircraft registered as C-GMPQ, was the most active during the summit. It flew a total of roughly 17 hours and 15 minutes, included one flight that lasted more than six hours.

Data: Author. Graphics: Marvin Lau

When asked for comment, Global Affairs referred questions to the RCMP which referred me to a press release that said the air space above Charlevoix was restricted from June 1 to 10 **“**to allow the Department of National Defence (DND) to safely manage participating air traffic in and around G7 activity areas,” but provided no details about the scope of the operation.

To see how the planes I identified contributed to this year’s sky-high costs, I roughly estimated the maintenance and fuel costs associated with flying the aircraft by looking at their flight time.

Using figures from the Pentagon, the price of flying the two Hercules aircraft I identified for around a hour would amount to about $13,000 CAD ($9,787 USD)). For the four Chinooks, that number would amount to approximately $49,000 CAD ($36,884 USD) for a two hour and 40 minute flight. Using estimates from air travel enthusiast site Sherpa Report, the RCMP incurred the highest costs with its planes that I identified, with a $69,000 CAD ($51,939 USD) price tag for 33 hours and six minutes of flight time. Fuel and maintenance costs are likely a small sliver of the whole operation’s costs.

Data: Author. Graphics: Marvin Lau

The G7 was a rare opportunity to see Canada’s security apparatus in action. Many of the RCMP planes I spotted over the weekend typically operate in different parts of the country, according to the Canada Civil Aircraft registry. But considering the Canadian government’s opacity, it is likely that their full capabilities will never be known.