I got the letter for the steering wheel airbag inflator (15S21) in July last year stating the issue and that parts were not available. Fast forward to May of this year, and I get the letter stating parts are available, make appt with dealer for the repair. I got the second letter the same day I was going in for an oil change, so I was able to get mine done at the same time. Just got the third recall notice (16S26) concerning the passenger airbag inflator, with the same issue of parts not available. Also had a nifty picture:
We'll just have to see how long it will take for the new parts to be available, but I don't expect it to be much sooner than the other one. It's not just Ford, most auto makers used Takata inflators, so I'm not surprised at how long it takes to produce the new parts. So my original plan of trying not to run into things is still in effect :-)