Ahh see, it only took a little poke to reveal exactly to whom the generally terrible advice to use an OTA applies to. Your extreme secrecy could've led someone to make that regretful choice.

Provided that ALL of the following applies to you, booking on Expedia makes sense, as you are otherwise protected by 24 hour cancellation policies:

1. Booking a flight that does not originate, terminate, or connect within the US.

2. Your ticket is not purchased from the US based office any airline.

3. Your ticket is not from any of the following airlines, regardless of place of purchase, as they all offer 24 hour cancellation irrespective of government rules:

Aegean Air Aegean Air policies Aer Lingus Aer Lingus policies Aeromexico Aeromexico policies AirAsia AirAsia policies Air Astana Air Astana policies Air Austral Air Austral policies Air Baltic Air Baltic policies Air Europa Air Europa policies Air France Air France policies Air India Air India policies Air Macau Air Macau policies Air Malta Air Malta policies Air Mauritius Air Mauritius policies Air New Zealand Air New Zealand policies Air Serbia Air Serbia policies Air Seychelles Air Seychelles policies Air Transat Air Transat policies Air Vistara Air Vistara policies Alaska Alaska policies Alitalia Alitalia policies All Nippon Airways All Nippon Airways policies American Airlines American Airlines policies Asiana Asiana policies Austrian Austrian policies Avianca Avianca policies Bangkok Air Bangkok Air policies British Airways British Airways policies Brussels Airlines Brussels Airlines policies Cathay Pacific Cathay Pacific policies Condor Condor policies COPA COPA policies Croatia Croatia policies Delta Delta policies easyJet easyJet policies El Al El Al policies Emirates Emirates policies Ethiopian Ethiopian policies Etihad Etihad policies Eurowings Eurowings policies EVA Airways EVA Airways policies Fiji Airways Fiji Airways policies Finnair Finnair policies Frontier Frontier policies Garuda Indonesia Garuda Indonesia policies GOL GOL policies Gulf Air Gulf Air policies Hainan Hainan policies Hawaiian Hawaiian policies Hong Kong Airlines Hong Kong Airlines policies Iberia Iberia policies Icelandair Icelandair policies Indigo Indigo polices Japan Airlines Japan Airlines policies JetBlue JetBlue policies Jetstar Jetstar policies KLM KLM policies Korean Korean policies LATAM Airlines LATAM policies LOT LOT policies Lufthansa Lufthansa policies Malaysia Malaysia policies Oman Air Oman Air policies Pegasus Pegasus policies Philippine Airlines Philippine Airlines policies Porter Airlines Porter Airlines policies Qatar Qatar policies Royal Air Maroc Royal Air Maroc policies Royal Brunei Airlines Royal Brunei Airlines policies Royal Jordanian Royal Jordanian policies Ryanair Ryanair policies SAS SAS policies Saudia Saudia policies Scoot Scoot policies Sky Express Sky Express policies South African Airways South African Airways policies Southwest Southwest policies Spirit Spirit policies Sri Lankan Sri Lankan policies Swiss Swiss policies TAP TAP policies Transavia Transavia policies Turkish Turkish policies UIA UIA policies United Airlines United Airlines policies Utair Utair policies Virgin Atlantic Virgin Atlantic policies Virgin Australia Virgin Australia policies Vueling Vueling policies West Jet WestJet policies

Now I don't know what "most airlines outside the US don't have 24 hr cancellation policies" constitutes. That list appears to represent what must be at least 98% of air passenger traffic.

I guess this airline for which Expedia offers 24 hour cancellation but the carrier doesn't will remain a mystery. A bit selfish to keep that a secret while directing people to use an OTA.