Traveling to crazy town

Ohio, the land of cold and snow.

I shall be traveling back to Ohio for a week. It will probably be cold. No 100% chance of cold! Ill be getting on the plane at 80 something degrees or higher. Then get off the plane at like 50 degrees or less. This is gonna be horrible.

Itinerary.
Get through security with two children alone.
Wait for plane.
Board plane.
Fly
Get off plane in chicago for layover.
Wait 2 hours for next flight.
Board plane.
Get to Columbus.
Be freezing.

Yeah this is gonna be a FUN plane ride. <---insert sarcasm. First plane ride for the girls. Dont worry B rode in a plane when she was in utero plane ride. Now 4 years old flying on a plane, her sister will be 17 months flying for the first time.

Any tips for flying with a 17 month old and a 4 year old by yourself? Ill be babywearing K so she shouldnt be to bad.