LiveTraffic's aircraft can be made available on your plane's TCAS and to other plugins, e.g. to display them on maps. Since X-Plane 11.50 there is a new dedicated mechanism for this purpose called TCAS Override. This new approach makes workarounds like configuring AI aircraft superfluous and allows to report up to 63 aircraft as compared to previously 19.

In earlier X-Plane versions (i.e. up to 11.41), LiveTraffic falls back to the previous way of emulating TCAS, which will require you to set up AI Aircraft in X-Plane's aircraft settings.

Here are 4 screenshots showing off the functionality of TCAS and multiplayer planes:

TCAS, Map, Little Navmap, FS Tramp

Many Many TCAS blibs

Near Hit

Very Close

TCAS, Map, Little Navmap, FS Tramp

3rd party tools FSTramp and Little Navmap showing (up to 19) multiplayer planes, while X-Plane's internal map and TCAS implementation in the Garmin G1000 show all traffic.

Many Many TCAS blibs

Showing off TCAS Override with uncounted (clearly more than 19) TCAS blibs...while there were no AI Aircraft configured.

Near Hit

What a dangerous situation looks like with another plane approaching and nearly hitting you...bad piloting skills 🤫​

Very Close

What a dangerous situation looks like with another plane approaching and nearly hitting you...bad piloting skills 🤫​

Does it work?

The following feedback I received. The last column "Uses TCAS Targets" tells you what we know about if that plane/tool is already adapted to use the up to 63 TCAS targets as data source, ideally with a specific versions since when it works.

*) For Pilot2ATC there are reports that it would show no planes when no AI Aircraft are configured. This seems to be a bug in XPUIPC, which is used to connect Pilot2ATC to X-Plane. Until that is fixed you need to have AI Aircraft configured when Pilot2ATC starts up.