the 2013 Macbook Air uses a PCIe based interface for the SSD. a USB case costs between $60 and $100. this was simply too much money to pay for a thing that I will use exactly one time. yes, I could have purchased one, used it, then returned it claiming I bought the wrong case. which is the stuff of an ethics cards game. and I am not opposed to venturing this as a fix. I just do not make a practice of it. what I wanted was a one way trip. you know, get the thing, fix the problem, send the result back to where it came from. fixed is the operative word.
my search efforts paid off when I noticed something different. it was a PCI card for a PCIe SSD. it was $1o. sold. Amazon got it here in two days. I installed the SSD, shut down the cheese grater, then powered on. the Mac asked to reconfigure the PCI bus to make the SSD even faster. the third option will do that, yes please. restart. [I forgot to snap a screen shot of this interesting configuration panel. oops.]
it took about an hour for Carbon Copy Cloner to make a bit image of the SSD. 4 gee bees a minute. that seems slow given the bus speed of PCI and that the SATA drive it was going to was SATA2. it should be more like 11 gee bees. hmph. with the image copied to spinning media, I cloned the clone to another hard drive that will fly away to Texas.
there might be issues with the SSD. this would explain why the MBA behaved badly. and why the SSD was slow to copy. more testing is required.
while this seemed like it took a long time my total time on the project, not counting waiting for parts to ship or copies to happen, was about 35 minutes. most of this was spent researching which benders to buy to read the SSD.
this is the link to the bender. currently out of stock but you can use it to find it from a different vendor.