Settings are available from X-Plane's menu:
Plugin > LiveTraffic > Settings.... In the "Basics" section you define if LiveTraffic is to show aircraft:
Show Live Aircraft
(depends on Auto Start)
Same as via menu
If enabled LiveTraffic starts querying the channels for live flight data and will soon begin showing aircraft.
Shall LiveTraffic enable Live Aircraft after startup?
Disable this if you want to control yourself when live aircraft are displayed.
This options can help running LiveTraffic in parallel with other multiplayer or traffic generation plugins:
TCAS on request only
If this is enabled then LiveTraffic will not try to control AI planes for TCAS simulation when starting to display aircraft. Then, if you want LiveTraffic to control AI/TCAS, you need to command so via menu item
Hide a/c while taxiing
If activated hides aircraft in phase "Taxi". Makes only sense if No a/c below is 0 because otherwise taxiing planes are hidden anyway.
This settings shall also ease integration with plugins for generating airport traffic.
No a/c below
[ft AGL] Aircraft flying below this height above ground are made invisible.
0 means: Don't hide anything, show all.
This shall allow integration with other plugins, which generate airport, taxi, and gate traffic while LiveTraffic takes care of the upper sky.
Note that hidden aircraft are just that: hidden. They are still tracked and computed and could be manually made visible.