An adaptive electronically steerable array (AESA) system suitable for use on a vehicle, the system comprising: a plurality of arrays, each comprising a plurality of radiating elements; and control circuitry to configure the arrays for multi-band and multi-aperture operations, wherein the control circuitry is configured to use a line-of-sight vector to direct the array for communications with a communication station as the vehicle maneuvers and to reconfigure the arrays to switch between communicating with a first communication station and a second communication station, wherein the control circuitry is further configured to switch between communicating within a first frequency band through a first aperture to communicating within a second frequency band through a second aperture, wherein the first and second frequency bands are widely-spaced frequency bands having at least a five percent carrier frequency separation, wherein the first frequency band is a higher-frequency band than the second frequency band, and characterised in that for the multi-band and the multi-aperture operations, the control circuitry: configures each element to operate as a single aperture for communicating within the first frequency band, and configures a plurality of two or more elements to operate as a single aperture for communicating within the second frequency band, wherein when two or more elements operate as a single aperture for communicating within the second frequency band the control circuitry is configured to coherently combine signals for the two or more elements for single-aperture operation. a plurality of arrays, each comprising a plurality of radiating elements; and control circuitry to configure the arrays for multi-band and multi-aperture operations, wherein the control circuitry is configured to use a line-of-sight vector to direct the array for communications with a communication station as the vehicle maneuvers and to reconfigure the arrays to switch between communicating with a first communication station and a second communication station, wherein the control circuitry is further configured to switch between communicating within a first frequency band through a first aperture to communicating within a second frequency band through a second aperture, wherein the first and second frequency bands are widely-spaced frequency bands having at least a five percent carrier frequency separation, wherein the first frequency band is a higher-frequency band than the second frequency band, and characterised in that for the multi-band and the multi-aperture operations, the control circuitry: configures each element to operate as a single aperture for communicating within the first frequency band, and configures a plurality of two or more elements to operate as a single aperture for communicating within the second frequency band, wherein when two or more elements operate as a single aperture for communicating within the second frequency band the control circuitry is configured to coherently combine signals for the two or more elements for single-aperture operation. configures each element to operate as a single aperture for communicating within the first frequency band, and configures a plurality of two or more elements to operate as a single aperture for communicating within the second frequency band, wherein when two or more elements operate as a single aperture for communicating within the second frequency band the control circuitry is configured to coherently combine signals for the two or more elements for single-aperture operation.