The prime principle of LiveTraffic is: LiveTraffic puts a plane where external tracking data demands it to be. Tracking data provides a position with a timestamp, about every 10-30 seconds per plane. LiveTraffic makes sure that at that reported point in time the plane is exactly at that reported position. Inbetween any two tracking data points, LiveTraffic needs to interpolate data at its own discretion. Eventually, LiveTraffic recalculates a plane's position with every drawing frame of X-Plane, ie. several dozen times per second!
The tracking data received from the channels, however, ...
can and will be inaccurate,
never includes all planes in the air,
is geographically restricted to the coverage the channels provide,
often misses moving planes on the ground as ADS-B receiver coverage is more difficult the lower a plane flies,
provides by design only positional data every few seconds but no reliable paths or vectors,
does not include situational or configuration info (pitch, roll; gear, flaps, ...).
The RealTraffic app provides an integrated radar view, see here for an example
You will at maximum see the same aircraft as show on their pages. Quite some big US airports have comparably bad data coverage, e.g. KSFO, KATL, KLGA, even KJFK.
Ground coverage is very much limited by the fact that the earth is round and ADS-B signals travel like all radio signals do: like a straight line: The radio signals an aircraft on the ground sends out can only be received by ground-based receives, which are very close to the aircraft, ie. very near to the airport. The signals cannot be received by receives behind the horizon or behind countless obstacles like buildings or forests. Good ground coverage requires that somebody operates an ADS-B receiver close to the airport.
There is an awful lot of data cleansing and take off / landing prediction in LiveTraffic, which tries try smoothing all of these effects, and we'll keep working on it...but it only works so far. In general, OpenSky seems to be a bit more accurate than ADS-B-Exchange.
As of now, LiveTraffic takes the following ground features into account:
Ground altitude is always considered as per scenery.
Runway detection for auto land is in as per v1.24.
Sinve v1.5, LiveTraffic also reads and uses taxiway and gate/ramp information (see here)
For the above mentioned processing LiveTraffic needs data. The more it is allowed to "look into the future" the better it is able to smoothen especially take off and landing. This buffering period, which is equivalent to the time lag as compared to reality, is configurable in the Advanced Settings and defaults to 90 seconds. There is an FAQ for more background on why buffering is needed.
All you hear is your own engines. As sound support is very high effort both in implementation and in getting open source sound samples, sound is not a functionality to come anytime soon.
With X-Plane before version 11.50 you may here sound from an AI Aircraft when a LiveTraffic aircraft is mapped to one of X-Plane's AI Aircraft. This is then the sound of the model that you configured as AI Aircraft.
With X-Plane 11.50 the way TCAS/multiplayer support is handled changed completely, so that no AI planes are supported any longer and can therefor not produce sound either.
Live aircraft will be where reality puts them regardless of your plane's position. They simply fly or drive through you if you are in the way. That can look funny if you are stopping short at the beginning of the active departure runway and a A380 performs its take-off roll through you.
You may, however, impersonate an existing plane and take over its queue position!
The Highlander issue: LiveTraffic is a multiplayer client like XSquawkBox, X-IvAp, xPilot, Swift, or PilotEdge are as well. All of them want to take control of TCAS Targets and/or the so-called multiplayer aircraft, also known as AI aircraft. These are the up to 19 additional aircraft X-Plane offers as a standard feature. Control over them is not needed for drawing planes into the sky. But only the controlling plugin can create TCAS blibs and can send data to 3rd party plugins like map or camera tools.
If multiple of those multiplayer clients are active only the first requesting access will get to control TCAS targets and/or multiplayer planes and controls what is seen on TCAS displays, the others fail.
LiveTraffic tries to play nice (see notes on parallel operation) but has no control over how other clients behave. And they often acquire access to the multiplayer planes but never release them if not deactivated the hard way in the plugin admin.
The XPMP2 Remote Client can be a solution to the problem as it can combine all traffic of XPMP2-based plugins (like LiveTraffic, xPilot) to be displayed on TCAS.
TCAS display implementations in add-on planes vary and are beyond my control. However, there is much positive feedback, so chances aren't too bad.
Just saying...you might be able to listen in some areas using services like Live ATC (here's a tip to synch timing), but no chance to interact. It means that if you intend to line up with the chain of aircraft approaching a busy runway you have to find and maintain your spot yourself. Same goes for take off. Good luck!
It is optimized for commercial jet and turbo prop planes. Should be OK for GA aircraft, might work for other fixed-wing aircraft, but will definitely fail for other types. Other types will still apear in the sky (their representation certainly depend on the installed CSL libraries), but LiveTraffic will do a bad job in supporting them to take off or land.
LiveTraffic is no videocast from your favorite airport. It will not at all reflect the skilled maneuvers, with which Q400 pilot's achieve impressive landings in crosswind storm conditions.
LiveTraffic will fill your sky and (to a certain extend) airports with planes as they are operating in real life. It's one more bit of realism in your simulator. If you find that pretty cool then LiveTraffic is worth a try!
You have been warned...especially following gliders on a busy weekend can be intoxicating!