Passengers on an Air Canada flight — to Toronto from Montreal — had to exit the plane on inflatable slides when it landed at Pearson International Airport. (CBC)

Unusual odours with seemingly unrelated causes disrupted two Air Canada flights from Montreal Tuesday morning.

An Air Canada Jazz flight en route to Halifax from Montreal was forced to turn back after the flight crew noticed a strong odour shortly after takeoff that was later attributed to a product used to clean the plane's engine the night before.

In a separate incident earlier Tuesday, passengers on another Air Canada flight — to Toronto from Montreal — were forced to make an emergency exit from the plane when it landed at Pearson International Airport.

There were 99 passengers and six crew aboard the Montreal-Toronto flight.

Saad Saade, one of the passengers who spoke with CBC News inside Pearson airport, said he had noticed a "weird smell" when he entered the Airbus A-320 aircraft in Montreal.

After a light went on indicating an issue, the pilot announced there was a problem with one of the plane's three hydraulic systems, but told passengers the problem had been isolated and they should not worry.

Call to tower

The pilot radioed the tower to say that the plane might need a tow to get off the runway.

To be safe, fire trucks would meet the aircraft when it touched down in Toronto, the pilot said to passengers.

Flight 433 landed safely just after 9 a.m., but crews came out to tow the aircraft. Passengers said the strange smell had worsened after touching down and 15 minutes after landing, a haze developed in the cabin.

When the haze became more evident, the plane was evacuated and emergency slides were used to get passengers out of the aircraft.

Air Canada spokesman Peter Fitzpatrick said the smoke passengers saw appeared to have come from hydraulic fluid in the brakes.

Minor injuries

Six of the passengers suffered minor scrapes and bruises, according to the airline. One passenger was treated at a hospital, but has since been released.

The odour on the Air Canada Jazz flight was noticed inside the cabin by the flight crew shortly after takeoff at around 9:15 a.m.

The pilot was asked to return to Montreal, where the plane, which had 50 people aboard, landed safely, said an Air Canada spokesperson.

Upon arrival at the airport, the two pilots and one crew member were checked by paramedics and taken to hospital as a precautionary measure, they said.

Passengers were transferred to another flight.

An inspection later linked the odour to the engine cleaning product.