Listening to the LiveATC.net recording posted above, we know thy were on the
RNAV (GPS) RWY 19L approach. The IAF-FAF segment of that approach (WITBA to WARUN) is on a true heading of 186, and passes directly above KAAO airport. At KAAO, the runway is perfectly aligned with the approach centerline, on a true heading on 187. The alignment is perfect. Looking at the approach, at WARUN there is a heading change to 192. So then flying WITBA-WARUN, the only airport with runway aligned precisely at 12 o'clock is KAAO, not KIAB. I can see the mistake happening, horizontally this is a good match.
How about the vertical profile? WITBA to WARUN is 9 miles. WITBA to KAAO runway threshold is 6.7 miles. At WITBA they must have been at 4000', per the approach plate. KAAO runway 18 threshold is at 1401'. So they had to come down 2600 feet in 6.7 miles. That's a 3.65 degree glideslope from WITBA to the KAAO runway. Again, the vertical glide is also pretty good, it they had interpreted WITBA as a FAF.
It will be interesting to see what the investigators find and what actions may be taken. I can see how a single mistake of confusing WITBA for WARUN would lead to this. Not excusable from a professional crew, but I can see it happening.
Now here is another thing... The KAAO NOTAM:
AAO 11/008 AAO AD AIRPORT CLSD 1311210347-1311272300
So they expect to fly out of there today, but the airport is to be closed until the 27th? Runway damage perhaps? DreamLifter too heavy for that runway?