A flight leaving Toronto's Billy Bishop Airport was diverted to suburban Toronto Pearson Airport soon after take off "when the crew detected smoke inside the aircraft" Porter said in a statement.
"One of the two engines was shut down using standard procedures and the aircraft landed safely," it said.
Two passengers aboard the Bombardier Dash 8 received medical attention for suspected anxiety- related issues and two flight attendants were seen by medical personnel as a precaution, Porter added.
Yesterday morning, another plane- Flight 723 from Toronto to Washington- was diverted to the small town of Williamsport, Pennsylvania, after smoke appeared in the cabin.
Its 66 passengers, who left downtown Toronto's Billy Bishop Airport at approximately 8 am, boarded another flight to the US capital, Porter said.
The airline did not immediately comment on the cause of the incidents.