A voice over internet protocol (VoIP) system for an aircraft includes a ground gateway, an aircraft gateway disposed on the aircraft, and a service provider network disposed on the aircraft. The ground gateway is in communication with the aircraft gateway via the service provider network. The aircraft gateway includes a first proxy agent, and the ground gateway includes a second proxy agent. The first proxy agent and the second proxy agent communicate a network packet for a number streams. The network packet includes a header and voice payloads for the streams.