XPLM_MSG_RELEASE_PLANES

#define XPLM_MSG_RELEASE_PLANES 111

Sent to your plugin if another plugin wants to take over AI planes. If you are a synthetic traffic provider, that probably means a plugin for an online network has connected and wants to supply aircraft flown by real humans and you should cease to provide synthetic traffic. If however you are providing online traffic from real humans, you probably don’t want to disconnect, in which case you just ignore this message. The sender is the plugin ID of the plugin asking for control of the planes now. You can use it to find out who is requesting and whether you should yield to them. Synthetic traffic providers should always yield to online networks. The parameter is unused and should be ignored.