I'm near Toronto Zone 5b I believe.

I guess I started some airlayers too late because no roots have grown. I opened the plastic bottle up and the fig stem has the little white nubs.

We are at the end of the season now.

Do I remove the the soil and bottle/airlayer from the stem and reapply in spring?

Do I leave the airlayer in place as is during the winter dormancy?

Tony

I did the same thing Tony just pull it off and start over in the Spring if you leave it on I believe it will rot the limb in the winter 

I find that for airlayer to be rooted, Tree needs to be in grow up mode, it means that it is growing leaves and branches, it is very hard to do it now because tree is in " Dormancy"  mode.

You may remove your air layer setup now and redo it next spring time.

I am doing easy airlayer now at suckers at below by adding bark/mulch cover up base of suckers, At spring time, 1 month after tree sprouts, I hope that it has some roots there.
Sorry, try to post a small picture of 90K but fail, Anyway, I host it to tiny picture website but not sure how long it last.

I will remove the air layers.

At this time of the season, I do not remove air layers, unless I see freezing temps coming. I usually keep them on the mother tree until the mother tree goes dormant. When that happens, I will remove the A/L and either pot up or leave them in their little root containers. You need to make sure that the medium gets some water during dormancy. The air layers cannot be exposed to freezing temps.