For anyone traveling to Tallinn 2023 and 2024 you can expect various interruptions and changes to tram and bus schedules.
There is a very large tram line project to link the harbor with the airport that has closed down many parts of the central city. This has affected the main city bus station (Viru Keskus) and the only tram line currently running is #6, thus there is no tram service to the airport but there are buses. If you are driving in Tallinn expect lots of detours and route changes every few days.. I have been using both Waze and Google Maps and both are pretty well updated. The work is supposed to be completed by the end of 2024 with various closures from now until then.
Here is a link to the Tallinn city website about the construction:
https://www.tallinn.ee/en/vanasadamatramm
Happy travels!