Which items may be omitted from subsequent transmissions after initial contact with an ATS unit?

The correct choice centers on the understanding of standard communication protocols with Air Traffic Service (ATS) units. After establishing initial contact, pilots are not required to repeatedly provide the aircraft type and the first two letters of the registration. This information is generally communicated at the outset of the flight and is assumed to be understood by the ATS unit.

This practice helps streamline communications, avoiding redundancy and allowing for more efficient dialogue as the flight progresses. Once the ATS unit has the pertinent aircraft identification, further transmissions can focus on other critical updates, such as changes in flight path, altitude, or other situational needs.

Other items listed in the options, such as the flight plan and intent to land, as well as departure airport and estimated time of arrival, are typically important for ongoing safety and traffic management, which is why they must be included in follow-up communications. Similarly, weather updates and fuel status can significantly affect flight safety and operational decisions, thus needing to be provided as conditions change.