Earlier quoted context omitted.
This looks like it was the two seat trainer version of the U-2 which doesn't carry mission equipment like the SYERS sensor or a data-link.
Would they really send a U-2 plane to pass by the balloon just to take a selfie?
I’m not a jingoistic person but even I felt a tinge of awe and American pride when I saw the photo. The U2 is cool, and this photo depicts the US as in control of the situation in a way that we didn’t feel when this thing was in the news.