Which procedure is correct for activating a VFR flight plan?

Activating a VFR (Visual Flight Rules) flight plan is correctly accomplished by contacting 1800wxbrief. This service provides a means for pilots to activate their flight plans via phone, ensuring that the necessary information is communicated directly to Air Traffic Control. By using this method, pilots can verify their flight plan is in the system and receive any pertinent weather updates or route changes.

Engaging with the other options reveals why they are not appropriate. For example, calling the airport manager may not facilitate activation of a flight plan, as they typically do not handle flight plan communications. Sending a text to Air Traffic Control is not an established method for activating plans and would likely not receive an official response. Filling out paper forms at the terminal may be part of filing a flight plan initially, but it does not satisfy the need for activation, which must be formally acknowledged by air traffic services. Therefore, using 1800wxbrief streamlines the process and aligns with standard aviation procedures.