Thank you for your message and for contacting Iowa State University.
The specimen in your photo is one of the woolly aphids (winged adult). For most of Iowa the common woolly aphid and the one seen flying as winged adults is the woolly alder aphid that lives on maple trees.
Woolly aphids on maples can be annoying but don’t cause significant harm to the trees, and the winged adults are harmless and so-darn-cute! I’ve seen more woolly alder aphids on maple this year than usual, but still think it is not damaging to otherwise healthy trees. A friend west of campus had a heavy infestation a couple years back. Tree was covered with honeydew. Tree is still there and doing fine. Maybe control over the patio is warranted to stop honeydew dripping on the picnic table, but otherwise, I wouldn’t bother.More details: http://www.ipm.iastate.edu/ipm/info/insects/true-bugs/woolly-alder-aphid