What was the object on the flatbed trailer being hauled through Dallas? Well, I can tell you what I believe it 'wasn't'. A poster commented that it is a wind turbine blade but I have to respectfully disagree.
(Click on images for larger view)
After having studied the design plans (spouse and I have an avid interest in wind energy), I'd have to again say "no". I've seen literally hundreds pass on trucks right in front of my home, on their way to be painted. I've seen them come undressed and then pass back by, decked out with a fresh coat of paint. Ever get stuck behind one at a downtown traffic light and they need to make a left turn and so do you? You are going to be there for a while. Those things are huge! The blades don't fit on regular flatbeds. There are trailers that are specifically built for the extremely long blades, in which individual blade lengths vary from 120 to 180 feet. The one in the photo doesn't look anywhere near that long, nor is it thin enough.
I also pass through a huge wind farm on Hwy 351, every time I go to the big town of Abilene (which is often). The photo I show as evidence, was taken on Aug. 3, 2009. I have some other interesting photos of that same wind farm, that I will post soon.
Second option, a stealth fighter plane. Possible but I haven't found one that looks close enough to say for sure.
Maybe it's a stuffed whale. Maybe not. Better still, a prop from an upcoming movie. We just don't know... but someone does.
The object remains a UTO (Unidentified 'Trailered' Object*).
*I think I may have coined a new phrase. :^)