Originally Posted by
redvelvetmartinis
This is interesting. Does this mean that if a Singaporean traveler has GE, he/she does not need to have the ESTA? Or is that still necessary?
(Would seem like a hassle to keep remembering to update, since GE validity is 5 years but ESTA is only 2 years)
Nope, GE is completely separate from ESTA (or Visas) - you still need an ESTA or Visa.
GE only speeds up the border crossing. An ESTA or a Visa is required for boarding flights and admittance into the USA. (I do know of people boarding flights without an ESTA, and no ESTA is required at land borders, so this isn't 100% true. The border processing will take longer in both of these cases though, and I have a feeling they'll be unhappy if you arrive by air without an ESTA.)