Don Muang airport is flooded, but the trains are still running, and the news has some amazing footage of trains sliding through a calm sea of water. Which reminded me of Chihiro or Spirited Away, a wonderful cartoon from Studio Ghibli of a theme park for the Gods surrounded by water. Dream World theme park is in flooded Patumthani too.
It also lets me see the flooding without actually getting in anyone's way. The flooding begins just south of Don Muang airport, the old airport (Suvarnabhumi is the current International Airport, which is for the moment safe behind its 3.5 metre embankment).
As you see from the video and the map below, the residences to the west are flooded to knee deep, with some of the lower slum ones completely filled. Some buses are still running, albeit with extra life savers in the back window and a lot of the people were heading home to the flooded areas, just with extra supplies.
The temple grounds are flooded but there's plenty of dry temple for homeless people to sleep in. People are simply getting on with their lives, the army has a regular truck service running on that road, so you can still get around, and volunteers wander around with free food making sure nobody goes hungry.
On the map I've marked with the green arrow, where the flooding begins, it starts just south of the airport and is to the north of that marker. The side streets are not flooded at first, but as you get a little deeper into the flooding, they're covered in water too.