Dism: How did I miss this?
Not-so-recently I dispensed with using optical installation media for pretty much everything. This of course includes Windows operating systems so I always have a 4GB flash drive on hand with whatever version of Windows I'm currently running. This is not always a happy-path sort of operation and today I found myself exasperated trying to install Hyper-V as "Add Windows Features" chugged along in vain doing God-knows-what as I waited impatiently. My expectation was that it would recognize my flash drive and that would be the end of it, but it was not to be. A quick web search yielded an answer more in the form of fishing lesson, than fish (much thanks to Andre Ziegler). Open an elevated command prompt and use the Deployment Image Servicing and Management tool (DISM) with the proper arguments and voila.
C:\WINDOWS\system32>Dism /online /enable-feature /all /featurename:Microsoft-Hyper-V /Source:h:\sources\sxs /LimitAccess
Deployment Image Servicing and Management tool
Version: 6.2.9200.16384
Image Version: 6.2.9200.16384
Enabling feature(s)
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