This was followed by a suggestion from councillor Barbara Donaldson that a laxative might help things along.
The LGWM group was set up following the signing of the Ngauraga to Airport Governance Group Memorandum of Understanding in 2014.
"2014 to 2019 is one hell of a long period", McKinnon said.
"Things lose credibility if they drag on too far."
The council was "punching in the dark" when it came to making other related transport decisions, he said.
That sentiment was echoed by fellow councillor Daran Ponter who said the significant delays were having a chilling effect for decisions including bus priority, walking access and cycling.
Even once the decision was released, the city and regional councils will have to endorse the proposal and then work out the practicalities, he said.
"We are probably some years away before we even see the soil being turned on some of these significant projects.
"So it has been a frustrating point to date but we're not out of the woods by any length in the near future."
A letter from regional council chair Chris Laidlaw and mayor Justin Lester hints getting that endorsement from councillors won't necessarily be easy.
The letter sent to the Transport Minister in February this year has been uncovered in a LGOIMA response provided to Wellington-based National list MP Nicola Willis.
The letter starts by thanking Phil Twyford for the opportunity to work with him "directly".
They have written in support of the proposal and say Cabinet's decision will allow them to share it in full with their respective councils.
"This decision will be challenging for some councillors, as you would expect, but having now reached consensus on the proposal we believe we can now work with our councils towards any necessary decisions."
The two council leaders say they're mindful of the need to "hit the ground running" following Cabinet's decision.
"In order to do that we need urgent decisions from the New Zealand Transport Agency to help us transition from our current development structure to an agile, responsive and capable delivery partnership".
Lester would not comment specifically on the letter.
He wanted to let the Government objectively make its decision.
"I want a good outcome for Wellington and I don't want to put any future investment at risk."
Lester has previously denied picking up the mantle for LGWM.