The Tesla’s patents related to the aeroplane are the following:

04/04/1921 GB185446: Method of and Apparatus for Aerial Transportation
04/03/1922 BE302,824: Procédé et appareil pour transports aériens (Manquant)
11/24/1922 FR549.628: Procédé et appareil pour transports aériens
05/07/1923 DK31663: Flyvemaskine
01/03/1928 US1,655,113: Method of aerial transportation
01/03/1928 US1,655,114: Apparatus for aerial transportation

There are probably patents for this invention in other countries. If you have any documents about the airplane, please let us know.