The Burlington, Ont., singer for the Juno-nominated band tweeted that she had been kicked off United flight 6223 Wednesday.
Blackwood was on a flight bound for Vancouver with her two-year-old son, Giorgio.
"Apparently my little two-year-old crying son was a big threat," Blackwood said on Twitter.
SkyWest Airlines operated the United flight, and said in a statement that the crew made the "difficult decision" based on security concerns.
"Despite numerous requests, the child was not seated, as required by federal regulation to ensure passenger safety, and was repeatedly in the aisle of the aircraft before departure and during taxi," the statement reads.
"While our crews work to make travelling safe and comfortable for all travellers, particularly families, the crew made the appropriate decision to return to the gate in the interest of safety."
Passenger says crew member 'insensitive'
Many people took to United's Facebook page to denounce the airline's move. Paul William Moore said he was on the flight Wednesday afternoon and was sitting two rows behind Blackwood. He said she was trying her best to keep her son quiet.
"The only person that was not empathetic to the clearly stressful situation was the flight attendant, who warned the mother three times to keep her kid quiet," Moore wrote. "Sure enough the flight attendant followed through on her warning and had the plane return from taxiing to position on the runway back to the airport."
By that time, Moore wrote, her son was fast asleep. "We then spent the next 75 minutes while the flight crew escorted the mother and child off the plane and the cargo crew removed all the luggage off the plane in order to find her bags."
"Everyone on that flight was shocked at how unprofessional, unreasonable and insensitive a certain member of your staff acted!"