I work for an airline and it happens sometimes, especially when there are two airports in the same area with the same controllers vectoring both airports.
VH
Approach control and Tower are on separate radio Frequencies.
Approach control vectors them to a final approach then tells them to switch to tower at the outter marker, usually about 6-7 miles from runway. Some regional airports in the US do not have towers. The airliner contacts on a unicom freq, to announce intentions. Possibly this is the case with Rapid City. I dont know. There could be as many as 4 or 5 different frequencies to use for ground to plane contact. If you figure that each radio freq is used to contact the plane and tried at least 2 times on each one, the plane would have already landed. As stated above, 7 miles is covered very quickly. There would have been absolutely no way to scramble fighters unless they were sitting alert at the end of the runway. Besides that, Ellsworth is a bomber base. I dont believe they even have fighters based there, but I may be wrong.
Ill wait to hear the final results of the investigation. No reason to get all bent out of shape and try to vanquish someone without all the details of what transpired.