City staff told council last week there are too many unanswered questions surrounding the proposal and recommended a decision on the island airport be pushed back to at least 2015.
Porter wants to extend both ends of the main runway — from 168 to 200 metres — to accommodate a new fleet of Bombardier CS-100 jets.
Flying jets out of the island airport would also require changes to the agreement between the city, the federal government and the Toronto Port Authority. Porter currently flies Q400 turboprops.
Both Deputy Mayor Norm Kelly and Mayor Rob Ford are in favour of expanding the runway but executive committee member Peter Milczyn said there remains too many unknowns.
He plans to move a motion that will essentially kill the passenger levy idea at Thursday's executive committee meeting, and says city staff must move on to other matters.
"We've done more than enough on this Porter-initiated proposal and … all the senior city that have spent months on this now they should be concentrating their efforts on the downtown relief line and other transit projects," he said.
The proposal will likely go to council later this month.