An aircraft freestream data system, comprising: a first ultrasonic air data system, UADS, configured to sense local acoustic properties at a first location on an aircraft; a first local air data module operatively connected to the first UADS and configured to determine first local air data of the first location and to output first local air data; a freestream data module operatively connected to the first local air data module and configured to: receive the first local air data from the local air data module; determine one or more freestream air data parameters based on at least the first local air data; and output the one or more freestream air data parameters to one or more aircraft consuming systems; a first static pressure sensor operatively connected to the first UADS and the first local air data module to provide first local static pressure data of the first location to the first local air data module; a second static pressure sensor located at a second location on the aircraft, the second static pressure sensor configured to provide second local static pressure data of the second location; a second UADS configured to sense local acoustic properties at a second location on the aircraft; and a second local air data module operatively connected to the second UADS and configured to determine second local air data of the second location and to output second local air data, wherein the freestream data module is operatively connected to the second local air data module and is further configured to: receive the second local air data from the local air data module; and determine the one or more freestream air data parameters based on at least the first and second local air data, wherein the first and/or second local air data parameters include at least one of a first and/or second local airspeed, a first and/or second local wind angle, and a first and/or second local speed of sound, a first and/or second local air temperature, or a first and/or second local Mach number, first and/or second local air density, or first and/or second local Reynolds number. a first ultrasonic air data system, UADS, configured to sense local acoustic properties at a first location on an aircraft; a first local air data module operatively connected to the first UADS and configured to determine first local air data of the first location and to output first local air data; a freestream data module operatively connected to the first local air data module and configured to: receive the first local air data from the local air data module; determine one or more freestream air data parameters based on at least the first local air data; and output the one or more freestream air data parameters to one or more aircraft consuming systems; receive the first local air data from the local air data module; determine one or more freestream air data parameters based on at least the first local air data; and output the one or more freestream air data parameters to one or more aircraft consuming systems; a first static pressure sensor operatively connected to the first UADS and the first local air data module to provide first local static pressure data of the first location to the first local air data module; a second static pressure sensor located at a second location on the aircraft, the second static pressure sensor configured to provide second local static pressure data of the second location; a second UADS configured to sense local acoustic properties at a second location on the aircraft; and a second local air data module operatively connected to the second UADS and configured to determine second local air data of the second location and to output second local air data, wherein the freestream data module is operatively connected to the second local air data module and is further configured to: receive the second local air data from the local air data module; and a second UADS configured to sense local acoustic properties at a second location on the aircraft; and a second local air data module operatively connected to the second UADS and configured to determine second local air data of the second location and to output second local air data, wherein the freestream data module is operatively connected to the second local air data module and is further configured to: receive the second local air data from the local air data module; and determine the one or more freestream air data parameters based on at least the first and second local air data, wherein the first and/or second local air data parameters include at least one of a first and/or second local airspeed, a first and/or second local wind angle, and a first and/or second local speed of sound, a first and/or second local air temperature, or a first and/or second local Mach number, first and/or second local air density, or first and/or second local Reynolds number.