Cockpit traffic displays do not necessarily show all other airplanes in the area. What pilots see depends on how their aircraft are equipped, the avionics in the target aircraft and the available services in between.
VFR flight following means that air traffic control (ATC) is tracking your aircraft in real time on radar systems and will provide you with traffic advisories, safety alerts, vectors when requested, hazardous weather information and assistance in an emergency. This service must be requested by pilots and is only available when controller workloads allow.
At some airports you may be able to reach ATC on the ground using the radio frequency listed for clearance delivery or approach control. Another option is to call clearance delivery directly on your phone. You can find the phone number for the overlying Air Route Traffic Control Center (ARTCC) listed in the Chart Supplement under in the communications section under “Clearance Delivery Phone.” You can also pick up an IFR clearance after you are airborne, providing you remain VFR until you get your clearance.
The problem with the right-of-way rules is that they not only rely on each aircraft being aware of the other but also that at least one of them is going to take appropriate avoiding action. Whomever has the right of way is essentially irrelevant if either pilot is unaware of the other traffic, and even if you think you have the right of way do you really want to rely on the other pilot to do the right thing?
The phrase “clear of the active” at non-towered airports is totally meaningless because all runways are potentially active. Just because you don’t see anyone else using other runways at any given moment doesn’t mean they are not active. You won’t find the phrase “clear of the active” mentioned anywhere in the FAA Pilot/Controller glossary and it is not sanctioned by the FAA.
UNICOM is a frequency pilots use to request airport information from a ground station which is monitored by FBO staff (not air traffic controllers). A Common Traffic Advisory Frequency (CTAF) is a designated frequency used at, and in the vicinity of, non-towered airports by pilots to self-announce their position and intentions to other pilots in order to avoid traffic conflicts. The CTAF will also be used at towered airports when the tower is not operating. The MULTICOM frequency, 122.9 MHz, may be designated as the CTAF on the VFR sectional for some small, non-towered, airports where there is no UNICOM. This frequency should also be used for self-announcing procedures at any airport where there is no published frequency mentioned on the chart or in the chart supplement, including private/restricted airports.