From the proclamation:
Sec. 5. Effective Date. This proclamation is effective at 11:59 p.m. eastern daylight time on March 13, 2020. This proclamation does not apply to persons aboard a flight scheduled to arrive in the United States that departed prior to 11:59 p.m. eastern daylight time on March 13, 2020.
So, I guess anybody making it onto any TATL w/b UA flight from EU on FR 3/13, should still be good!
This would mean that most TATL EU e/b flights on TH 3/12 could still operate.
https://www.whitehouse.gov/president...l-coronavirus/