The F-16I Sufas loaded with AIM-120s can stay airborne for more than four hours before going Bingo.
To increase that time, you need to create another "Support" mission, this time for your Saknayee tankers.
As before, put a couple of Reference Points on the map and press "Ctrl + F11" to create a new mission. Select "Support" and add the two 707 tankers.