The spelling of the name of the City of Jaú changed as time went by. Jahú is the name of the river that crosses the city and of a fish found in that river.
Due to the successive spelling reforms, the sharp accent was abolished, the name remaining, therefore, JAHÚ (with an "h" and without accent).
The aeroplane "JAHÚ" - in capitals, bold, and with a sharp accent o the "u" - indicates the aircraft, as it was named at the time of the flight.
Municipal Act nº 481, of March 21st, 1988, which deals with the spelling of the word "JAHÚ", reads, in its Article 1:
"The word "JAHÚ", when referring to the city or to the municipality of Jaú, will be officially written with an "h" in the middle, such as it occurs with the toponymic "Bahia", thus written according to Rule nº 42 of the 143 Orthography Act, rendered official by Federal Decree nº 14.533, of January 18th, 1944".