A lot of confusion on this thread, but most here seem to have it right:

1) the USA does NOT check your passport on departure

2) the check by the AIRLINES (not the government) on check-in for a departing flight is to establish that you have the proper documents needed to ENTER the DESTINATION country, nothing to do with your EXIT from the USA


It hadn't occurred to me before the stupidity of USA "emergency passports" having a validity of only six months, as most countries require passports to be valid for a minimum of six months from date of entry, making such passports useless in most cases.

Yet another case of brilliant thinking on the part of the DHS.