I am also having the glitch in the very same spot after the same event as described by the original poster. I shoot down the aircraft, then the loading screen comes up, and stays there for ever until the monitor goes into power save mode.
I have Googled around and seen a few people that have brought this issue up in Steam and Armaholic forums. No one seems to know why it happens or have a solution. It bothers me because I had the same problem with ARMA 2, and have yet to finish a campaign because I have a life and can't replay 4 hour segments from the beginning.
But considering the slew of bugs this game has, we have to count our blessings that it doesn't fry our motherboards. I have the latest patched version of the game through steam, as steam keeps it up to date automatically.