Originally Posted by
sinoflyer
For an accurate answer, input the details of the pax's itinerary including the origin, destination, and intermediary points, as well as the pax's passport nationality and country of residence to TIMATIC on UA's website (as well as other airlines'):
www.united.com/en/us/timatic
That is great to always check Timatic...though our answers were accurate, for the record. Unless you are a citizen of the three other CFA countries(Palau, Marshall Islands, FSO Micronesia), LPR, Canada, or are on certain refugee travel documents (and OP noted ineligible for ESTA) one needs a C-1 transit visa or other visa that can get them through.
There is no mechanism for sterile transit used in the US right now and that is not changing anytime soon.
Even trying via a preclearance does not change the rule.
As an aside I found an error in Timatic while checking in for a Belize trip last week, that UA even opened a ticket on with them to update, but I digress.