A Chinese balloon likely blew off course and should have been “knocked out of the sky” before straying into United States’ airspace, says an aviation expert.

The balloon was likely used for surveillance and espionage purposes, aviation expert and Strategic Aviation Solutions chairman Neil Hansford said.

“I’m not sure they ever meant for it to go over the US mainland, he told The New Daily.

“I think they may have lost control of it due to the winds and other factors and it probably wasn’t planned to be where it was.”

Balloons or satellites for spying?

Mr Hansford said the use of balloons, while common for monitoring weather, were not often used by countries for their spy networks.

Most countries, including the Five Eyes – an intelligence alliance comprising Australia, Canada, New Zealand, the United Kingdom and the United States – rely on satellites to gather intelligence.

Mr Hansford said the use of balloons raises questions about China’s ability to collect covert intelligence and casts doubts on their claims of superior technological advancements.

“Why you would use balloons and not what’s capable from satellites? It’s very questionable,” he said.

“Depending on what the balloon was actually carrying … it’s not [technology] that’s much improved beyond that of post Second [World] War.”

Expert slams US response

Mr Hansford was critical of the US response, saying “they should have knocked it out before it came across from the Pacific”.

The US military shot down the balloon on Saturday, ending its week-long voyage through US airspace.

A cheering crowd of onlookers gathered at Myrtle Beach, South Carolina, to watch missiles from an F-22 fighter strike the balloon. It quickly collapsed and fell into the ocean.

Scroll through the panels below for a timeline of the saga:

The US Navy and Coast Guard are working to recover the balloon.

A successful recovery could potentially give the US insight into China’s spying capabilities, though US officials have downplayed the balloon’s impact on national security.

Difficult time

The episode has caused alarm and made it more difficult for President Joe Biden to foster a positive relationship with China.

Pentagon spokesperson Brigadier General Pat Ryder said that instances of this kind of balloon activity have been observed in the past several years.

Once the balloon was detected, the US government acted immediately to protect against the collection of sensitive information, he said.

However, the Biden administration’s handling of the situation has been criticised by some.

Amy B Zegart, a senior fellow at the Hoover Institution, said it “is not comforting” that similar crafts have been previously sighted.

“We should have had a strategy earlier,” she said, “[and] we should have signalled our limits much earlier.”

Republicans have accused President Biden of waiting too long to shoot down the balloon and of showing weakness towards China.

“It’s sort of like tackling the quarterback after the game is over. The satellite had completed its mission. It should never have been allowed to enter the United States, and it never should have been allowed to complete its mission,” chairman of the House intelligence committee, Republican Michael R. Turner said.

Democrats, on the other hand, believe that Mr Biden’s decision to wait until the balloon had passed over the US protected civilians from debris crashing to Earth.

“The President called for this to be dealt with in a way that balanced all of the different risks. That’s exactly what happened,” US Transportation Secretary Pete Buttigieg said on CNN’s State of the Union program.

Biden was cautious with the balloon. Photo: AAP

Senate Democratic Leader Chuck Schumer dismissed the Republican criticism as “premature and political”.

“The bottom line here is that shooting down the balloon over water wasn’t just the safest option, but it was the one that maximised our intel gain,” he said at a news conference.

Spy craft through the years

From the Cold War to today, aircraft have been a critical tool in the spy trade for nations worldwide.

From the legendary U-2, also known as the Dragon Lady, to the super-fast Lockheed SR-71 Blackbird, spy planes have played a crucial role in intelligence gathering, surveillance and reconnaissance.

The U-2, developed by the US in the 1950s, was the trailblazer in high-altitude reconnaissance, flying at 70,000 feet, beyond the reach of most anti-aircraft weapons.

The SR-71 Blackbird was the epitome of speed and agility, capable of Mach 3 flight and equipped with cutting-edge sensors and cameras for long-range intelligence gathering.

In the 1950s the US military launched a top-secret military reconnaissance program using balloons.