I'm using something like that.
I created my own php script and i run it with a cronjob.
It keeps my schedule databse up to date and I grab data from Flightaware totally free.
Basically, the scrip go to
$ch = curl_init("http://flightaware.com/live/fleet/".$code."?;offset=".($i*40)."&sort=ASC;order=actualdeparturetime");
$code is defined by whatever you want ( WJA-JBU-AAL-DAL...)
The script is connected directly with your phpvms database so it updates/upload all datas in there.
If flight does not exist = it creates
If flight exist = check for update
if exist and up to date = do nothing
and also, if flight do not receive any update for x days, then delete it
So you understand here that my schedule is always up to date and synchroinized with flightaware
I'm pretty proud of it because i'm not a php expert and I'm working on it for one year lol
I used flightaware API before but I found out a way to get data for free...