Some West Island residents are upset after learning that the night flights at Montreal's Pierre Elliott Trudeau International Airport are reverting back to the old schedule.

For the past two and a half years, the flights leaving between midnight and 7 a.m. have been using a path that takes them north over Ville St. Laurent. Now, the flights will use a path that takes them out over the lake.

The switch is because the airport could not get the planes to take off steeply enough to fulfill Transport Canada's Noise regulations.

Residents in St. Laurent, Cartierville, Saraguay and Ahuntsic had been battling that flight plan.

Now, West Island resident Paul Wilkinson is concerned about the change back to the old routes.

"[These flights] are causing hypertension, and hypertension leads to heart attacks," he said. "We shouldn't be inflicting it on the population in Dorval, Pointe-Claire, St Laurent or anywhere in Canada."

However, the head of the ADM, James Cherry, says he does not believe that the noise or pollution of the flights can negatively impact residents' health.

"A lot of that research has been brought up in many other places and it has never been proved to be credible," he said.

The organization says there are between 10 and 20 flights nightly, and they are well below Transport Canada's noise regulations.

Dorval Mayor Edgar Rouleau says he is still concerned about the health and sleep schedules of his residents.

"Our major problem is at night," he said. "During the day, people accept [it] because we live close to an airport. But from midnight to six, everybody should be entitled to sleep."