The UK will conduct a security review after a series of objects in Western airspace were shot down by the US military, including a suspected Chinese spy balloon.
The Defence Secretary announced the intended review on Sunday.
It comes after US fighter jets shot down an "unidentified object" over Lake Huron on Sunday – the fourth object to enter US or Canadian airspace in just over a week.
Ben Wallace said: "The UK and her allies will review what these airspace intrusions mean for our security.
"This development is another sign of how the global threat picture is changing for the worse."
On 4 February, the US military downed a suspected Chinese spy balloon off the Carolina coast after it traversed sensitive military sites across North America.
Almost a week later on Friday, they shot down an unknown "car-sized" object flying in US airspace off the coast of Alaska.
Prime Minister Justin Trudeau said on Saturday that he ordered a US warplane to shoot down an unidentified object that was flying high over northern Canada.
On Sunday, a further unidentified object was shot down with a missile by US fighter jets over Lake Huron.
China admitted the first balloon to appear in US airspace Chinese was theirs but insisted that it is a weather balloon that was blown off course.
Military balloons have historically been used by militaries around the world since the 18th Century.
Taking off in the First World War, more recently, balloons are relatively low-tech compared to alternatives.
Offering the opportunity to achieve lofty surveillance ambitions on the cheap, with some experts believing state actors could turn to greater use of the balloon, once more.
A balloon may also offer advantages a satellite might not.
Rebekah Koffler, CEO of Doctrine and Strategy Consulting, told Forces News with a balloon you have "an intelligence collection asset that is much closer to the ground".
"What you've got is likely a multi-sensor package, you have a high-resolution camera and you have other sensors."