Got the following from United a while back for an upcoming trip to the Baltics and Balkans
Enjoy a worry-free return to the U.S. with Abbott.
We've partnered with Abbott to provide a COVID-19 test kit you can bring on your trip to Vilnius and almost any future international trips.* Pack it in your carry-on, take the test within three days of your return flight to the U.S. and enjoy your trip knowing you won't have to search for a COVID-19 test in another country.
See how it works
Abbott's rapid BinaxNOW™ Home Test meets the CDC's requirements for entry to the U.S. You can order it below or by visiting the Travel-Ready Center.
Our first-of-its-kind partnership with Abbott is another reason you can feel confident when you fly with us.
It comes in a pack of 6 and costs $150 - so averages to $25. I read somewhere that you should carry 2 just in case. You need to download an app and register before leaving the US. You also need internet access so someone can verify it is you taking the test while on camera.
I plan on ordering mine shortly
Edit - apologies for the font size - not sure what happened when I cut and pasted
The following is a link to a short Youtube video that United attached in the email. Test takes about 30 minutes and you can do it from your hotel room.