> Avoiding radar via “cloaking technology” has long been one of the objectives of the defence industry and Freescale has been active developing chips for military radar.
You forget one thing. The radar used by commercial airlines is transponder based. Instead of transmitting a pulse and listening for an echo at the tower, they wait for the individual airplanes to broadcast their position and identity. Anyone wanting to disappear just shuts off the transponder. They can still be picked up using radar, but air traffic controllers probably wouldn’t notice it.
So, cloaking would not be used, but failing to transmit identifying signals would.