A modular payload system for an aircraft includes a modular bay recessed within the aircraft. The modular bay includes a modular bay interface. The modular payload system includes a plurality of payload modules each having a respective function and a payload interface adapted to connect to at least a portion of the modular bay interface. The plurality of payload modules are interchangeably insertable into the modular bay to enable the modular bay to support the functions of the plurality of payload modules.