Here, hold my beer. I want to take a selfie of me and the balloon.
Text: So rays from the sun are “collimated” (parallel) meaning the U2’s shadow should ~match its actual size. Taking the 65’ length of the U2 and seeing it is about half the diameter of the balloon, you get ~130’. This matches the “3 school buses”
number given by the DoD (40-45’ each).
Also: The balloon is roughly 2 U-2's (1 U-4) long, equivalent to 3 school buses, 265 Standard Bananas or 1.4 blue whales. Hope this helps
Finally: Our Best Look Yet At The Chinese Spy Balloon’s Massive Payload
https://www.thedrive.com/the-war-zone/our-best-look-yet-at-the-chinese-spy-balloons-massive-payloadFrom the above article: The bulbous shape of the front end of this shadow had raised a question about whether the aircraft from which the selfie was taken could actually have been a two-seat TU-2S trainer. DOD
Four eyes are better than two.