For more details about Flarm, Fanet and Livetracking, check this FAQ.
The Flarm module integrated in AIR³ 7.3+ is using 868 MHz data communication frequency currently. This is the one used by FLARM in EU.
North and South America are mainly using 915 MHz, so AIR³ 7.3+ will not work for FLARM in Americas unless you are flying in a zone with aircrafts using 868 MHz.
Note that most AIR³ competitors proposing a similar FANET and FLARM module for paragliding are using the same module for Fanet and Flarm as the one used with AIR³. So, the same limitation to 868 MHz only frequency should occur.