Couldn't find any ref to this when searching , so here goes...

Be aware that Expedia says paper tickets will be sent via "express mail" on their website,
But in actuality they may mail them via USPS, or ship them via UPS, at their choice, when you select the option ( and pay $19.99 ).

Confusingly, "Express Mail" is a registered trademark of the US Postal Service.

...AND...the terms "express mail" and even "mail" is carefully avoided by the United Parcel Service ( UPS ). You won't even find anything they deliver referred to as "mail" on their website. UPS is very careful... the only place it is referred to is their "expedited mail" service.. .which is when UPS turns things over for final delivery to the USPS, explicitly.

Why this matters is if one orders paper tickets for home delivery... and have USPS currently holding mail on vacation hold. and actually think that Expedia is shipping via "mail", or "express mail" like they say on their customer service page.

If shipped via UPS,
-- it may be returned to Expedia and you'll have to call up for a reshipment
( and they better not charge for this! )
-- the UPS person may just leave it (even if signature required ) on your doorstep
-- you may need go to the UPS Service Center ( a 2 hour roundtrip, taking vacation time from my work , mid day, for me. ).

... Hotwire, for comparison, explicitly says that it may be sent express mail or shipped via UPS to avoid such confusion for their customers.

Hopefully this entry will help others avoid getting into a similar situation.