Just out of curiosity, what's your ISP and country? A daily reconnect sounds very familiar to what Fritz!Box routers in Germany are configured to do on DSL by default, but that's not needed with most ISPs in Germany anymore. So if you're in Germany, you might as well disable that to fix this altogether if the ISP is right.
Otherwise, I'd probably drastically lower connection timeouts. The OpenVPN default is 120 seconds, AirVPN servers push 60, and you might be able to lower this to 10 or even 5 if you need. Pay some attention to your connections when setting this so low, as OpenVPN will forcibly reconnect, no matter if the line is under high load or it's really a disconnect. Add this to the config:
ping-restart 10
.