Method of transmitting a message between a tanker aircraft and a receiver aircraft during an in-flight refueling operation performed by means of a boom device deployable from the tanker aircraft and connectable to a receptacle of the receiver aircraft, the boom device and the receptacle comprising coils (17, 18) which allow establishing an electro-magnetic connection between the two aircraft (11, 13) when they are connected for performing a refueling operation, characterized in that the message comprises a data message and a voice message and in that the method comprises the following steps: a) providing in the aircraft that emits the message a digital data frame (24, 94) containing the data message and a control signal (29, 99) and an analog audio signal (21, 91) containing the voice message and a control signal (23, 93) for its sending; b) converting in the aircraft that emits the message: - the digital data frame (24, 94) into a digital data signal (25, 95) and transforming this signal into an analog data signal (26, 96) conditioned to a suitable voltage level for its transmission to the target aircraft of the message; and - the analog audio signal (21, 91) into a second analog audio signal (22, 92), conditioned to a suitable voltage level for its transmission to the target aircraft and filtered to remove frequencies above a predetermined frequency f1, and mixing the second analog audio signal (22, 92) with the analog data signal (26, 96) for obtaining an analog audio and data signal (27, 97); c) transmitting the signal obtained in the previous step to the target aircraft via said electro-magnetic connection; d) separating the analog data signal (26, 96) and the analog audio signal (22, 92) contained in the analog audio and data signal (27, 97) received in the target aircraft and transforming the received signal (26, 96) into the digital data signal (25, 95) and converting this signal into the digital data frame (24, 94). a) providing in the aircraft that emits the message a digital data frame (24, 94) containing the data message and a control signal (29, 99) and an analog audio signal (21, 91) containing the voice message and a control signal (23, 93) for its sending; b) converting in the aircraft that emits the message: - the digital data frame (24, 94) into a digital data signal (25, 95) and transforming this signal into an analog data signal (26, 96) conditioned to a suitable voltage level for its transmission to the target aircraft of the message; and - the analog audio signal (21, 91) into a second analog audio signal (22, 92), conditioned to a suitable voltage level for its transmission to the target aircraft and filtered to remove frequencies above a predetermined frequency f1, and mixing the second analog audio signal (22, 92) with the analog data signal (26, 96) for obtaining an analog audio and data signal (27, 97); - the digital data frame (24, 94) into a digital data signal (25, 95) and transforming this signal into an analog data signal (26, 96) conditioned to a suitable voltage level for its transmission to the target aircraft of the message; and - the analog audio signal (21, 91) into a second analog audio signal (22, 92), conditioned to a suitable voltage level for its transmission to the target aircraft and filtered to remove frequencies above a predetermined frequency f1, and mixing the second analog audio signal (22, 92) with the analog data signal (26, 96) for obtaining an analog audio and data signal (27, 97); c) transmitting the signal obtained in the previous step to the target aircraft via said electro-magnetic connection; d) separating the analog data signal (26, 96) and the analog audio signal (22, 92) contained in the analog audio and data signal (27, 97) received in the target aircraft and transforming the received signal (26, 96) into the digital data signal (25, 95) and converting this signal into the digital data frame (24, 94).