The proposed expansion of Toronto’s Billy Bishop island airport is facing significant delays moving forward, according to a senior city official.

Deputy city manager John Livey said that staff and council are a “long way away from advancing” a proposal that would see the airport's runway extended to accommodate Bombardier CS-100 jets operated by Porter Airlines.

In the spring, Livey and city staff outlined a lengthy set of criteria that must be met before any expansion would be considered in a report that, among other recommendations, called for limits to passenger volume at the airport.

The report also pointed to a number of outstanding questions regarding the runway expansion, such as the need for an environmental assessment and the absence of a detailed design plan.

The Toronto Port Authority is expected to begin the environmental assessment sometime in early 2015, but a host of other data remains elusive — including information from Transport Canada about how the potential noise generated by the specific model of airplane that Porter wants to fly.

Nearly 190 people spoke before the city’s executive committee in March, many pointing to a seeming lack of information needed to make a reasonable decision on the proposal.

Livey said that many of the steps needed to generate crucial data “continue to get deferred and delayed.”

“Back in the spring, there seemed to be a great amount of urgency to find a way of bringing this to a conclusion,” said Livey.

“I outlined a lot of the missing pieces. I thought we would be able to address those issues simultaneously but it looks like it will be more one at a time.”

Livey said it could take until next autumn before the proposal comes back before city council.