Could, perhaps, "military in nature" be a description of a
jet as opposed to what a less than knowledgable witness would expect a civilian craft to be such as a Cessna 172? Or maybe, a Learjet at high speed and low altitude could also give an on-looker a false impression? I live in the approach and departure path of Raleigh/Durham International (RDU) and on many occasions small private business jets have beat hasty departures to which visiting friends have questioned if they were military jets.
I can appreciate the questions asked in the article but descriptions such as "military in nature" without a reliable source for such a description is borderline Michael Rivero-esque. In such cases, not always though, chances are that the simplest explanation is probably the most accurate. IMHO
Could be I guess.