Proponents of alien crashed flying saucers at Roswell and Aztec, such as Stan Friedman, have speculated that perhaps advanced radar systems brought the spacecraft down. Indeed, in this clip from the doc I made about the so-called Aztec incident, Aztec 1948, both Stan and Scott Ramsey talk about that possibility, while Karl Pflock offers a much more reasonable and sensible analysis.
You can view my deconstruction of the silly "radar brought the flying saucers down" claims here.
Fact vs. fiction in New Mexico. Unfortunately, the ufologists supplied the fiction, the same kind you will find with Frank Feschino's wild claims of an air war in the 1950s between the USAF and aliens, which have been "shot down" by more sensible UFO researchers like Jerry Clark and Dick Hall.