went looking for more on Ancestry, here's what i've got so far:
CRB (alternatively
CRDB), white female born July 10, 1949. Married a man with same last initial in September 1967 (when CRB was 17 and her husband was 26), and gave birth to a daughter that same year. Lived in Indiana her whole life. According to the family tree, CRB went missing in Indiana -- possibly Monroe County if I'm understanding these trees right -- in May or June 1971 (when she was 21 years old); the description on the tree says "Death not confirmed--declared missing"
PJB, white male born March 21, 1949 (though
one tree says 1950) in Brooklyn.
Very little information available; not even the year he disappeared. The two trees hyperlinked directly above state "missing 40 years";
this one, which I'm assuming is older than the other two, says "missing 35 years." With this + the fact that Ancestry rolled out the family tree creator feature in 2006 in mind, it seems that PJB went missing sometime between c. 1971 to 1991? Likely sometime closer to the start of that range, given that there is
no info about him past the 1950 census (at least, none that can be verified as him), but that's just speculation on my part.
Unsure if this one counts I guess, but
CRD, white male born 1950 in Atlanta. Plane went missing over West Palm Beach on Nov. 23, 1970. Officially declared dead on July 23, 1979. The linked tree has multiple articles about the search for the plane
EB, b.Feb. 14, 1949 in Ohio. I've found some records up to
1982. Missing since 1990. The trees in the Ancestry search results are saying she went missing from Bas-Rhin, Alsace, France, but when I click on the tree nothing about France comes up
here's a sorta rapid-firing of more that i've found but can't take the time to fully summarize right now:
JWB, b.1949, missing since [?]. Someone with same name except slightly different surname spelling has records up to at
least 2002, but unknown if this is the same person
JGF, b. June 24, 1949 in Houston, missing since [?]. Alt spelling
GGF. Listed as survivor in mother's 1991
obituary. Can't find anything else past the 1950 census [Note: he is
not this J/
GF]
DO, b. Dec. 1949, last record in tree 1994, listed as missing from TX
DAT, b. Apr. 1949, grew up in Los Angeles, missing after 1967
and idk you take these, but here are some American citizens who seem to have gone missing in other countries (and don't seem to be military):
JLH, May 1976, Ecuador
WHL, 2002 or later, Brazil
DRG, c.1982, Thailand