The ban on flying INTO THAILAND for FOREIGNERS has been EXTENDED thru April 30, 2020
"Prohibited passenger aircraft to fly into the airport in Thailand temporarily from April 19, 2020 at 00.01 hrs. Until April 30, 2020 at 23.59 hrs."
(also note that ALL LAND AND SEA entries remain CLOSED)
TLDR : Answer Summary
As of the latest update, the ban on foreign passenger flights into Thailand has been extended until April 30, 2020. This includes a prohibition on all land and sea entries, which are also closed during this period.