This code has been tested using Arduino IDE 1.8.5
Make sure you have installed the esp8266 tools version 2.4.0-rc2 by ESP8266 Community.
1.-Arduino >> Preferences >> Additional Boards Manager URLs>> add this:
https://github.com/esp8266/Arduino/releases/download/2.4.0-rc2/package_esp8266com_index.json
2.-Then go to:
Arduino >> Board: “Any Arduino Board” >> Boards Manager.. >> esp8266 by ESP8266 Community >> Install 2.4.0-rc2 (or release version).
3.-If for any reason you can’t see or use the 2.4.0-rc2, maybe is because the final version has been already released, so try again by adding this link to Additional Boards Manager and repeat the steps. : http://arduino.esp8266.com/stable/package_esp8266com_index.json
4.-Try to compile the board and upload it to your ESP8266 compatible devices.
5.-Connect your serial input to your MavLink sources.
6.-Connect your iPad to SSID “mRo ESP8266” and password “1234567890”.
7.-Open ForeFlight and Enjoy!
Send beers!