Yes. ForeFlight Mobile connects to select Garmin avionics via the Flight Stream 110, 210, and 510, Garmin’s family of Bluetooth wireless gateways, enabling convenient two-way flight plan transfer (Flight Stream 210 and 510 only, requires a compatible Garmin navigator) and the display of subscription-free ADS-B weather and traffic, backup attitude, and GPS position on your iPad and iPhone.
ForeFlight can also connect to Garmin's GTX 345 ADS-B Out transponder to receive GPS, AHRS, pressure altitude, and ADS-B weather and traffic information with select models. This transponder can connect to ForeFlight directly via Bluetooth, and does not require a Flight Stream. You can learn more about ForeFlight Connect for Garmin avionics here.