TORONTO -- Porter Airlines says it's fine with either of the expansion plans it has proposed for the Billy Bishop Toronto City Airport.

In June, the airline had proposed to extend the island airport runway by 168 metres at each end by filling in part of the lake so it can fly its new fleet of jets.

But on Tuesday, Porter proposed extending the runway by a total of 400 metres -- or 200 metres at each end. It said the extra few metres will give the planes additional take-off runway distance and will minimize noise.

The airline says both options are "equally viable."

Opponents from a group called NoJetsTO said in a statement Wednesday that the airline is "backpedalling" because of the scrutiny it has faced over its revised plan.

But Porter Airlines says it is simply clarifying, and that the longer extension would help to silence noise -- one of the concerns about Porter's bid to fly jets.

"We want to be clear that we have now presented two runway designs for the city to review as part of its process," said Robert Deluce, president and chief executive of Porter Airlines, in a statement.

"The 168-metre proposal is still a very good option and one that we support. The 200-metre option is another scenario that provides other benefits we believe are worth considering."

Porter has asked the city, Transport Canada and the Toronto Port Authority to amend a tripartite agreement that prevents jets from using the island airport except under special circumstances.

It has already placed a conditional order with Bombardier for 12 CS100 aircraft, with 18 options, worth about US$2.08 billion.

The greater range of the CS100 will allow the airline to fly to destinations like Los Angeles, Florida, Calgary and the Caribbean from Toronto.

If Porter's plan is approved, the first new planes are expected to be delivered in 2016.